JP5208831B2 - Vehicle skid motion state quantity estimation device - Google Patents

Description

  The present invention relates to a vehicle side-slip motion state quantity estimation device that estimates a side-slip angle or a side-slip speed of the center of gravity of a vehicle as a state quantity of a side-slip movement of a vehicle.

  In order to control the behavior of the vehicle, it may be necessary to estimate the state amount of the side-slip motion of the vehicle, such as the side-slip angle or the side-slip speed of the center of gravity of the vehicle. As the estimation technique, for example, a technique found in Patent Document 1 is known. In this technology, while estimating the friction coefficient of the road surface, the road surface reaction force (friction force) acting on each wheel of the vehicle from the road surface is estimated using the estimated value of the friction coefficient and the friction characteristic model of the wheel. . Then, the lateral acceleration of the center of gravity of the vehicle that is dynamically generated is estimated based on the sum of the lateral forces of the vehicle (the resultant force) of the estimated road surface reaction force. Then, the temporal change rate of the skid angle of the center of gravity of the vehicle is estimated based on the dynamic motion model of the vehicle from the estimated value of the lateral acceleration, the detected value of the vehicle speed, and the detected value of the yaw rate of the vehicle, By integrating this temporal change rate, an estimated value of the side slip angle of the center of gravity of the vehicle is obtained.

Japanese Patent No. 3669668

  As seen in Patent Document 1, the road surface reaction force (friction force) acting on each wheel of the vehicle is estimated, and the skid motion of the vehicle is calculated by the calculation of a dynamic motion model based on the estimated value of the road surface reaction force. In the technique for estimating the state quantity of the vehicle, the estimated value of the road surface reaction force eventually affects the estimated value of the state quantity of the side-slip motion of the vehicle.

  The estimated value of the road surface reaction force is easily affected by the non-linearity of the friction characteristics of the wheels (friction characteristics with the road surface), errors in the friction characteristics model, etc. In the transition period in which the road surface changes, generally the accuracy of the estimated value of the road surface reaction force tends to decrease. As a result, the accuracy of the estimated value of the state quantity of the side-sliding motion of the vehicle tends to be lowered. In addition, the road surface reaction force acting on each wheel of the vehicle is affected by the bank angle (cant angle) of the road surface, and even if the state amount of the side-slip movement of the vehicle is constant, the bank angle (cant angle) of the road surface is The road surface reaction force changes according to the change.

  However, in the technique shown in Patent Document 1, the accuracy of the road surface reaction force decreases due to a decrease in the estimated value of the road surface reaction force in the transition period when the friction coefficient of the road surface and the motion state of the vehicle change, and the road surface reaction force due to the change in the bank angle of the road surface There is no technology to compensate for the effects of change. For this reason, in the technique shown in Patent Document 1, the accuracy of the estimated value of the state quantity of the side-slip motion of the vehicle is reduced particularly in a transition period in which the friction coefficient of the road surface, the vehicle motion state, or the bank angle of the road surface changes. There was an inconvenience that it was easy to do.

  The present invention has been made in view of such a background, and improves the estimation accuracy of the state quantity of the side-slip motion of the vehicle including the transition period in which the friction coefficient, the motion state of the vehicle, or the bank angle of the road surface changes. An object of the present invention is to provide a vehicle side-slip motion state quantity estimating device capable of

In order to achieve this object, the vehicle side-slip motion state quantity estimation device of the present invention uses a side-slip angle or a side-slip speed at a predetermined position of the vehicle as a target side-slip motion state quantity, and sequentially calculates the value of the side-slip movement state quantity. A device for estimating,
Including a friction characteristic model representing a relationship between slippage between a vehicle wheel and a road surface and a road surface reaction force acting on the wheel from the road surface, and using a vehicle model expressing the dynamics of the vehicle, at least on the vehicle model By performing an arithmetic processing of the vehicle model while inputting an observation value of a predetermined type of observation target amount related to the actual vehicle behavior necessary for specifying the slip of the vehicle wheel at the vehicle model, A road surface reaction force model value that is a value of a road surface reaction force including at least a lateral force out of road surface reaction forces acting on each wheel of the vehicle on the vehicle model from the road surface is obtained, and a resultant force of the road surface reaction force model value Vehicle model computing means for obtaining a skid motion state quantity model value that is a value of the skid motion state quantity generated in a vehicle on the vehicle model;
A predetermined position actual lateral that includes at least a lateral acceleration sensor that is sensitive to the actual lateral acceleration of the vehicle and that generates an output in accordance with the predetermined actual lateral acceleration that is the actual lateral acceleration of the predetermined position of the vehicle; Acceleration detection means;
Using the road surface reaction force model value, a predetermined position lateral acceleration model value, which is a value of a lateral acceleration of the vehicle, in which a resultant force of the road surface reaction force model value is generated at the predetermined position in the vehicle on the vehicle model. A lateral acceleration model value calculation means to be obtained;
Lateral acceleration deviation calculating means for obtaining a lateral acceleration deviation which is a deviation between a detected value of the predetermined position actual lateral acceleration indicated by the output of the predetermined position actual lateral acceleration detecting means and the predetermined position lateral acceleration model value;
A yaw angular acceleration detecting means for generating an output corresponding to an angular acceleration around a predetermined yaw axis of an actual vehicle;
Yaw angular acceleration for obtaining a yaw angular acceleration model value, which is a value of angular acceleration generated around the predetermined yaw axis in the vehicle on the vehicle model, by using the road surface reaction force model value. Model value calculation means;
A yaw acceleration deviation calculating means for obtaining a yaw angular acceleration deviation which is a deviation between the detected value of the angular acceleration indicated by the output of the yaw angular acceleration detecting means and the yaw angular acceleration model value;
Side slip movement state quantity estimated value determination is performed by determining a value obtained by correcting the side slip movement state quantity model value according to the side acceleration deviation and the yaw angular acceleration deviation as an estimated value of the actual side slip movement state quantity of the vehicle. Means (first invention).

  The “observed value” in the present invention is an indirect value using a suitable model or a natural law from a detected value directly observed from a certain sensor output or one or more sensor outputs related to the observation target quantity. Means the estimated value observed in

  According to the first aspect of the invention, the vehicle model calculation means uses the vehicle model and at least a predetermined type of behavior related to actual vehicle behavior necessary for specifying the slip of the wheel of the vehicle on the vehicle model. The road reaction force model value is obtained by performing calculation processing of the vehicle model while inputting the observation value of the observation target amount to the vehicle model. In this case, more specifically, for example, the slip of each wheel of the vehicle is specified (estimated) based on the dynamics of the vehicle from the observation value of the predetermined type of observation target amount, and the slip is used as the friction characteristic model. By inputting, it is possible to obtain the road surface reaction force model value that is a value of the road surface reaction force including at least the lateral force among the road surface reaction forces acting on each wheel of the vehicle.

  Note that the observed value of the predetermined type of observation target amount is the observation target amount necessary for specifying the slip between the wheel and the road surface in the friction characteristic model based on the vehicle dynamics used in the vehicle model. The observation target amount may be selected according to the structure of the vehicle model including the friction characteristic model. Further, the side-sliding motion of the vehicle depends on the driving / braking force and the lateral force, which are frictional forces among the road surface reaction forces acting on each wheel, and is particularly highly dependent on the lateral force. Therefore, it is desirable that the road surface reaction force model value to be obtained is a road surface reaction force value including at least the lateral force of each wheel.

  Then, the vehicle model calculating means generates the vehicle surface on the vehicle model by the resultant force of the road surface reaction force model value obtained as described above (the resultant force of the road surface reaction force model value for all the wheels of the vehicle on the vehicle model). A skid motion state quantity model value that is a value of the skid motion state quantity is obtained. In this case, since the resultant force of the road surface reaction force (mainly the resultant force of the lateral force) acts on the vehicle as an external force, the movement of the vehicle is dynamically defined. For example, each wheel of the vehicle The road surface reaction force model value is input to a dynamic model representing the relationship between the road surface reaction force acting on the vehicle and the lateral movement of the vehicle at the predetermined position, and the calculation of the dynamic model is performed. By doing so, the model value of the skid motion state quantity can be obtained.

  For example, based on the dynamic relationship between the resultant force of the road surface reaction force of each wheel on the vehicle model and the temporal rate of change of the skid motion state amount, and the road surface reaction force model value, the road surface reaction force By calculating the temporal change rate of the side-slip motion state quantity resulting from the resultant force of the model value, and integrating the temporal change rate sequentially (cumulative addition to the past calculated value of the side-slip motion state quantity), the skid motion The state quantity model value can be obtained sequentially. In addition, when integrating the temporal change rate of the skid motion state quantity, a past calculated value (preferably the latest value of the past calculated values) of the skid motion state quantity is required. There are a form using a past calculated value of an exercise state quantity model value and a form using a past calculated value of an estimated value of a skid movement state quantity.

  In the first invention, the predetermined position actual acceleration detecting means generates an output corresponding to the predetermined position actual lateral acceleration, while the resultant force of the road surface reaction force model value of each wheel obtained by the vehicle model calculating means is A predetermined position lateral acceleration model value, which is a lateral acceleration value of the vehicle generated at the predetermined position in the vehicle on the vehicle model, is calculated by the lateral acceleration model value calculation means using the road reaction force model value. Desired. The lateral acceleration model value calculation means may be included in the vehicle model calculation means. Further, when the lateral acceleration sensor is mounted at the predetermined position of an actual vehicle, the output of the lateral acceleration sensor functions as it is as an output indicating the actual lateral acceleration of the predetermined position. On the other hand, when the mounting position of the lateral acceleration sensor is different from the predetermined position of the actual vehicle, for example, the output of the lateral acceleration sensor and the yaw rate sensor (or yaw angular acceleration mounted on the vehicle) are detected. Output corresponding to the actual lateral acceleration at the predetermined position can be generated from the output of the sensor.

  Then, a lateral acceleration deviation, which is a deviation between the detection value of the predetermined position actual lateral acceleration indicated by the output of the predetermined position actual lateral acceleration detecting means and the predetermined position lateral acceleration model value, is obtained by the lateral acceleration deviation calculating means. .

  Further, in the first invention, the yaw angular acceleration detection means generates an output corresponding to the angular acceleration around the predetermined yaw axis of the actual vehicle, while the road surface reaction of each wheel obtained by the vehicle model calculation means. A yaw angular acceleration model value, which is a value of angular acceleration generated around the predetermined yaw axis in the vehicle on the vehicle model, is calculated by the yaw angular acceleration model value calculation means by the yaw angular acceleration model value calculating means. It is calculated using. The moment around the yaw axis of the vehicle (and consequently angular acceleration) generated by the resultant reaction force of the road surface acting on each wheel is highly dependent on the lateral force of the road surface reaction force. By including at least lateral force, the yaw angular acceleration model value can be appropriately obtained using the road surface reaction force model value.

  Then, the yaw angular acceleration deviation calculating means calculates a yaw angular acceleration deviation which is a deviation between the detected value of angular acceleration indicated by the output of the yaw angular acceleration detecting means and the yaw angular acceleration model value.

  Here, according to the study by the present inventor, the friction coefficient of the road surface and the motion state of the vehicle change, particularly in a situation where the bank angle (cant angle) of the road surface on which the vehicle is traveling is kept substantially constant. During the transition period, the lateral acceleration deviation is significantly affected by the error of the side-slip motion state quantity model value with respect to the actual side-slip motion state quantity value (true value) of the vehicle. Therefore, in such a situation, it is considered that the estimated value with higher accuracy than the skid motion state quantity model value can be appropriately obtained by correcting the skid motion state quantity model value according to the lateral acceleration deviation. .

  On the other hand, since the lateral acceleration sensor of the predetermined position actual lateral acceleration detection means is generally sensitive to gravitational acceleration, the detection value of the predetermined position actual lateral acceleration detection means indicated by the output of the predetermined position actual lateral acceleration detection means includes the road surface. Has a bank angle (a bank angle other than “0”), the component in the direction parallel to the actual road surface in the lateral direction of the vehicle of the influence of the bank angle (more specifically, the gravitational acceleration acting on the vehicle) ) Will be included. Therefore, in a transition period in which the bank angle of the road surface changes, even if the actual side-slip motion state quantity of the vehicle is constant (even if the actual motion state of the vehicle is a steady state), the bank of the road surface The lateral acceleration deviation changes according to a change in angle. In such a situation where the lateral acceleration deviation changes due to the change in the bank angle of the road surface, the value obtained by the correction is obtained by correcting the skid motion state quantity model value according to the lateral acceleration deviation. However, the actual skid motion state quantity (true value) of the vehicle may deviate from the actual value.

  According to the study of the inventor of the present application, the lateral acceleration deviation changes due to the change in the bank angle of the road surface, and the lateral acceleration due to the change in the friction coefficient of the road surface and the motion state of the vehicle. Comparing the situation where the acceleration deviation changes, the former situation and the latter situation tend to differ in the combination of the polarity of the lateral acceleration deviation and the polarity of the yaw angular acceleration deviation.

  Therefore, in the first invention, the side-slip motion state quantity estimated value determination means determines a value obtained by correcting the side-slip motion state quantity model value according to the side acceleration deviation and the yaw angular acceleration deviation as an actual vehicle. It is determined as an estimated value of the state of skid motion state.

  As a result, in the transition period in which the friction coefficient of the road surface and the vehicle motion state change, the estimated value of the vehicle skid motion state amount is a value (true value) of the actual skid motion state amount rather than the model value of the side slip motion state. The estimated value of the skid motion state quantity can be determined by correcting the skid motion state quantity model value so as to be closer. As a result, the accuracy of the estimated value of the skid motion state quantity of the vehicle in the transition period in which the friction coefficient of the road surface and the motion state of the vehicle change can be made higher than the model value of the skid motion state quantity. Further, in a situation where the lateral acceleration deviation changes due to a change in the bank angle of the road surface, the side slip movement state quantity model value is prevented from being corrected in accordance with the lateral acceleration deviation, and the side slip is suppressed. It is possible to prevent the estimated value of the velocity motion state quantity from deviating from the actual value (true value).

  Therefore, according to the first aspect of the present invention, it is possible to improve the estimation accuracy of the state quantity of the side-slip motion of the vehicle including the transition period in which the friction coefficient, the motion state of the vehicle, or the bank angle of the road surface changes.

  In the first invention, the predetermined position of the vehicle includes, for example, the position of the center of gravity of the vehicle (second invention).

  According to the second aspect of the invention, it is possible to improve the estimation accuracy of the skid motion state quantity at the position of the center of gravity of the vehicle.

  In the second aspect of the invention, the predetermined position lateral acceleration model value is obtained by calculating the value of the translational force component in the lateral direction of the vehicle in the resultant force of the road surface reaction force model value obtained by the vehicle model calculation means as the vehicle mass. It can be obtained as a value of acceleration obtained by division.

  In the first invention or the second invention, more specifically, for example, the following configuration can be adopted. In each aspect described below, “*” means a multiplication symbol.

  In the first aspect, the vehicle model calculation means sequentially calculates a new value of the skid motion state quantity model value using the road surface reaction force model value and a past calculated value of the skid motion state quantity model value. The skid motion state quantity estimated value determining means is configured to have two weighting factors (α1) and (α1) for multiplying the lateral acceleration deviation (A) and the yaw angular acceleration deviation (B), respectively. A linear combination value calculation means for obtaining a linear combination value (α1 * A + α2 * B) obtained by linear combination using α2) and a basic value of a correction operation amount for correcting the skid motion state quantity model value are determined. A correction basic value determining means and a value obtained by passing the basic value through a first filter having a high-cut characteristic, or a gain multiplying means for multiplying the input value by the first filter and a gain of a predetermined value. Value above Used as a positive operation amount, configured to have a correction calculating means for determining the correction manipulated variable as an estimate of the side slip motional state amount of the actual vehicle a value that is in addition to the side slip motional state quantity model value. In this case, the two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) have the leftward direction toward the front of the vehicle as a positive direction of the lateral acceleration of the vehicle, and When the counterclockwise direction when the vehicle is viewed from above is defined as the positive direction of angular acceleration around the yaw axis of the vehicle, the actual vehicle's neutral steer point (hereinafter referred to as NSP) is the center of gravity of the vehicle. The two weighting factors (α1) and (α2) have the same polarity when they are present on the rear side, and the two weighting factors (α1) when the NSP is present on the front side of the center of gravity of the vehicle. ), (Α2) are set to have different polarities. Then, the correction basic value determining means determines that the linear combination value (α1 * A + α2 * B) has a different polarity from the term (α1 * A) including the lateral acceleration deviation (A) in the linear combination value. If “0” is determined as the basic value and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the lateral acceleration deviation (A), Of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A), a value closer to “0” is determined as the basic value (third invention).

  In the second aspect, the vehicle model calculation means uses the road reaction force model value and the previously calculated value of the skid motion state quantity model value as a new value of the skid motion state quantity model value. The side-slip motion state quantity estimated value determining means is configured to sequentially obtain a second filtering value (A) obtained by passing the lateral acceleration deviation through a second filter having a low cut characteristic, and the yaw The third filtering value (B) obtained by passing the angular acceleration deviation through the third filter having the low-cut characteristic is linearly combined using two weighting factors (α1) and (α2) applied to each. A linear combination value calculating means for calculating a linear combination value (α1 * A + α2 * B) and a correction basic for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value. A value obtained by passing the basic value through a first filter having a high-cut characteristic, or a value obtained by passing the basic value through the first filter and a gain multiplying unit that multiplies an input value by a gain of a predetermined value. And a correction calculation means for determining a value obtained by adding the correction operation amount to the side-slip motion state amount model value as an estimated value of the actual side-slip motion state amount of the vehicle. In this case, the two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are directed leftward toward the front of the vehicle, as in the first aspect (third invention). Is defined as the positive direction of the lateral acceleration of the vehicle, and the counterclockwise direction when the vehicle is viewed from above is defined as the positive direction of the angular acceleration around the yaw axis of the vehicle. When a steer point (hereinafter referred to as NSP) is present behind the center of gravity of the vehicle, the two weighting factors (α1) and (α2) are of the same polarity, and the NSP is greater than the center of gravity of the vehicle. The two weighting factors (α1) and (α2) are set to have different polarities when they are present on the front side. Then, the correction basic value determining means determines that the linear combination value (α1 * A + α2 * B) has a different polarity from the term (α1 * A) including the lateral acceleration deviation (A) in the linear combination value. If “0” is determined as the basic value and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the lateral acceleration deviation (A), A value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) is determined as the basic value (fourth invention).

  In other words, the fourth invention (second aspect) is different from the third invention (first aspect) only in the linear combination value calculation means, and the A in the linear combination value (α1 * A + α2 * B). Instead of the lateral acceleration deviation, the second filtering value obtained by passing the lateral acceleration deviation through the second filter is used as the value of B, and the value of B in the linear combination value (α1 * A + α2 * B) is used. As a result, instead of the yaw angular acceleration deviation, a third filtering value obtained by passing the yaw angular acceleration deviation through the third filter is used.

  In the third and fourth aspects of the invention, the vehicle model calculation means calculates the new value of the skid motion state quantity model value as the road surface reaction force model value and the past calculated value of the skid motion state quantity model value. Therefore, the estimated value of the skid motion state quantity as a value obtained by correcting the skid motion state model value is not fed back to the process of sequentially calculating the skid motion state model value, and the skid motion state The quantity model value is calculated without depending on the estimated value of the skid motion state.

  In this case, according to the study of the present inventor, the friction coefficient of the road surface and the motion state of the vehicle change, particularly in a situation where the bank angle (cant angle) of the road surface on which the vehicle is traveling is kept substantially constant. In the transition period, a value obtained by passing the lateral acceleration deviation through a filter having a low-cut characteristic and an integrating unit that integrates an input value is a skid speed at a predetermined position of the vehicle corresponding to the skid motion state model value. It approximates the error to the actual value (true value).

  Further, the process of passing the lateral acceleration deviation through the filter having the low cut characteristic and the integrating means for integrating the input value as described above is equivalent to the process of passing the lateral acceleration deviation through the filter having the high cut characteristic, or The processing can be replaced with processing that passes through the filter and gain multiplication means for multiplying the input value by a predetermined value of gain. When this replacement is performed, the integration means that easily accumulates calculation errors can be omitted.

  Further, for example, in the third invention, when the two weighting factors (α1) and (α2) are set as described above, the lateral acceleration deviation (A) changes due to a change in the bank angle of the road surface. In such a situation, the term (α2 * B) including the yaw angular acceleration deviation (B) in the linear combination value (α1 * A + α2 * B) (hereinafter, this term may be referred to as the second term) is There is a tendency to have a polarity different from the polarity of the term (α1 * A) including the lateral acceleration deviation (A) (hereinafter, this term may be referred to as the first term).

  On the other hand, in a situation where the lateral acceleration deviation changes due to a change in the friction coefficient of the road surface or the motion state of the vehicle, the second term (α2 * B) in the linear combination value is the first term. There is a tendency to have the same polarity as (α1 * A).

  In addition, the situation where the linear combination value (α1 * A + α2 * B) has a different polarity from the first term (α1 * A) is that the first term (α1 * A) and the second term (α1 * B). Are different in polarity, and the absolute value of the second term (α1 * B) is larger than the absolute value of the first term (α1 * A). For this reason, this situation is considered to be a situation where the influence of the change in the bank angle of the road surface is strongly generated.

  In addition, the situation where the linear combination value (α1 * A + α2 * B) has the same polarity as the first term (α1 * A) is that the first term (α1 * A) and the second term (α1 * B) Have the same polarity, the first term (α1 * A) and the second term (α1 * B) have different polarities, and the absolute value of the first term (α1 * A) is The situation is one of the situations that are larger than the absolute value of the second term (α1 * B). For this reason, this situation is considered to be a situation in which the bank angle of the road surface is constant or the influence of the change is weak, and the influence of the change in the friction coefficient of the road surface and the motion state of the vehicle is strongly generated. . Further, in this situation, the first term (α1 * A) and the second term (α1 * B) have different polarities, and the absolute value of the first term (α1 * A) is the second term (α1 In a situation where the absolute value of * B) is larger, the linear combination value (α1 * A + α2 * B) is closer to “0” than the lateral acceleration deviation (A) (the absolute value of the linear combination value). The value may be smaller than the absolute value of the lateral acceleration deviation).

  The matters relating to the polarity of the linear combination value described above and the polarity of each term of the linear combination value are the same in the fourth invention.

  In the fourth aspect of the invention, instead of the lateral acceleration deviation itself, a second filtering value obtained by passing the lateral acceleration deviation through a second filter having a low cut characteristic is used, and instead of the yaw angle acceleration deviation itself. In addition, a third filtering value obtained by passing the yaw angular acceleration deviation through a third filter having a low cut characteristic is used. For this reason, when a steady offset component is included in the lateral acceleration deviation or the yaw angular acceleration deviation due to the drift of the output of the lateral acceleration sensor or the yaw angular acceleration detection sensor, the offset component Can be removed. For this reason, even when the lateral acceleration deviation or yaw angular acceleration deviation includes a steady offset component, the phenomenon relating to the polarity of the linear combination value and the polarity of each term of the linear combination value appears remarkably. Cheap.

  Based on the phenomenon described above, in the third aspect of the invention, as described above, the correction basic value determining means determines that the linear combination value (α1 * A + α2 * B) is the lateral acceleration deviation (A) at the linear combination value. When the polarity is different from that of the term (α1 * A) including “0”, “0” is determined as the basic value, and the linear combination value (α1 * A + α2 * B) includes the lateral acceleration deviation (A). In the case of the same polarity as the term (α1 * A), a value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) is set to the basic value. Determine as.

  Similarly, in the fourth aspect of the invention, as described above, the correction basic value determining means includes a term in which the linear combination value (α1 * A + α2 * B) includes the second filtering value (A) in the linear combination value ( When the polarity is different from α1 * A), “0” is determined as the basic value, and the linear combination value (α1 * A + α2 * B) includes the second filtering value (A) (α1 When the same polarity as that of * A) is determined, a value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) is determined as the basic value. .

  The basic value thus determined reflects the above-described polarity relationship between the first term (α1 * A) and the second term (α1 * B), and the lateral acceleration deviation (A) It has a meaning as an adjusted value.

  In the third and fourth aspects of the invention, the correction calculation means of the skid motion state quantity estimated value determining means is a value obtained by passing the basic value determined as described above through the first filter having a high cut characteristic, or the basic value. Is used as the correction manipulated variable, and the value obtained by adding the corrected manipulated variable to the skid motion state quantity model value is actually used. It is determined as an estimated value of the skid motion state quantity of the vehicle.

  Thus, according to the third and fourth aspects of the present invention, in the situation where the lateral acceleration deviation changes due to a change in the friction coefficient of the road surface or the movement state of the vehicle, the linear combination value or the lateral acceleration deviation is reduced. Accordingly, a value obtained by appropriately correcting the skid motion state quantity model value (a value obtained by adding a correction operation amount to the skid motion state quantity model value) can be determined as an estimated value of the skid motion state quantity, The accuracy of the estimated value can be made higher than the skid motion state quantity model value. Further, in a situation where the lateral acceleration deviation changes due to a change in the bank angle of the road surface, it is suppressed to correct the skid motion state quantity model value according to the lateral acceleration deviation, or The correction is not performed. In other words, the amount of change in the estimated value of the skid motion state quantity from the skid motion state quantity model value is limited to be relatively small, or the estimated value of the skid motion state quantity is calculated as the model value of the skid motion state quantity. Determined to be the same value. For this reason, in a situation where the actual side-slip motion state quantity is kept constant, the estimated value of the side-slip motion state quantity is actually changed due to the change in the bank angle of the road surface that affects the lateral acceleration deviation. It is possible to prevent a situation in which the value fluctuates inappropriately or deviates from the actual value.

  In particular, in the fourth aspect of the invention, even when a steady offset component is included in the lateral acceleration deviation or yaw angular acceleration deviation, the influence can be eliminated. Therefore, it is possible to prevent a situation in which the skid motion state quantity model value is inappropriately corrected due to a drift of the output of the lateral acceleration sensor or the yaw angular acceleration detection sensor. As a result, the accuracy and stability of the estimated value of the skid motion state quantity can be further increased.

  Supplementally, in the third and fourth inventions, the first filter may be a filter having a low cut characteristic in addition to a high cut characteristic (that is, a band pass filter). In the fourth invention, the second filter and the third filter may be filters having a high cut characteristic in addition to a low cut characteristic (that is, a band pass filter).

  By the way, in the first invention or the second invention, in the calculation process of the skid motion state quantity model value in the vehicle model computing means, the skid motion state quantity is estimated as a value obtained by correcting the skid motion state quantity model value. The value is fed back to the process of sequentially calculating the skid motion state quantity model value, and when calculating a new skid motion state quantity model value, instead of the past calculated value of the skid motion state quantity model value, the skid motion state A form in which a new skid motion state quantity model value is calculated using a past calculated value of the estimated value of the quantity may be employed.

  In this case, when the value obtained by correcting the skid motion state quantity model value with the correction manipulated variable is determined as the estimated value of the skid motion state quantity, the corrected amount is calculated by calculating the skid motion state quantity model value. Will be integrated. Therefore, in this case, the integration means (integration means for passing the lateral acceleration deviation) described with respect to the third and fourth inventions is substantially included in the calculation process of the skid motion state model value. . For this reason, in this case, the first filter and the gain multiplication means having the high cut characteristics described with respect to the third and fourth inventions can be omitted.

  Therefore, in the first invention or the second invention, not only the first and second aspects but also the following aspects can be adopted, for example.

  In the third aspect, the vehicle model calculation means uses the road reaction force model value and a previously calculated value of the estimated value of the skid motion state quantity as a new value of the skid motion state quantity model value. The side-slip motion state quantity estimated value determining means is configured to have two weighting factors (α1) for multiplying the lateral acceleration deviation (A) and the yaw angular acceleration deviation (B), respectively. A linear combination value calculation means for obtaining a linear combination value (α1 * A + α2 * B) obtained by linear combination using (α2) and a basic value of a correction operation amount for correcting the skid motion state quantity model value are determined. A correction basic value determining means for performing the correction, and using the basic value or a value obtained by passing the basic value through a fourth filter having a low-cut characteristic as the correction operation amount, and adding the correction operation amount to the skid motion state quantity model value Become Configured to have a correction calculating means for determining as the actual estimate of the side slip motional state amount of the vehicle. In this case, the two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are directed leftward toward the front of the vehicle as in the third and fourth inventions. When the positive direction of the lateral acceleration is defined and the counterclockwise direction when the vehicle is viewed from above is defined as the positive direction of the angular acceleration around the yaw axis of the vehicle, When a point (hereinafter referred to as NSP) exists behind the center of gravity of the vehicle, the two weighting factors (α1) and (α2) have the same polarity, and the NSP is ahead of the center of gravity of the vehicle. The two weighting factors (α1) and (α2) are set to have different polarities. Then, in the correction basic value determining means, as in the third aspect, the linear combination value (α1 * A + α2 * B) includes the term (α1 * A) including the lateral acceleration deviation (A) in the linear combination value. ) Is determined as the basic value, and the linear combination value (α1 * A + α2 * B) includes a term (α1 * A) including the lateral acceleration deviation (A) and In the case of the same polarity, a value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) is determined as the basic value (fifth invention). ).

  Further, in the fourth aspect, the vehicle model calculation means uses a new value of the skid motion state quantity model value as the road surface reaction force model value and a previously calculated value of the estimated value of the skid motion state quantity. The side slip motion state quantity estimated value determining means includes a fifth filtering value (A) obtained by passing the lateral acceleration deviation through a fifth filter having a low-cut characteristic; The sixth filtering value (B) obtained by passing the yaw angular acceleration deviation through the sixth filter having the low-cut characteristic is linearly combined using two weighting factors (α1) and (α2) applied to each. A linear combination value calculating means for calculating a linear combination value (α1 * A + α2 * B) and a correction base for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value. A value determined by using a value determining means and the basic value or a value obtained by passing the basic value through a fourth filter having a low-cut characteristic as the correction operation amount, and adding the correction operation amount to the skid motion state quantity model value Correction calculating means for determining as an estimated value of the actual skid motion state quantity of the vehicle. In this case, the two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are directed leftward toward the front of the vehicle as in the third and fourth inventions. When the positive direction of the lateral acceleration is defined and the counterclockwise direction when the vehicle is viewed from above is defined as the positive direction of the angular acceleration around the yaw axis of the vehicle, When a point (hereinafter referred to as NSP) exists behind the center of gravity of the vehicle, the two weighting factors (α1) and (α2) have the same polarity, and the NSP is ahead of the center of gravity of the vehicle. The two weighting factors (α1) and (α2) are set to have different polarities. In the correction basic value determining means, as in the fourth aspect, the linear combination value (α1 * A + α2 * B) includes the term (α1 * A) including the fifth filtering value (A) in the linear combination value. ), The term “0” is determined as the basic value, and the linear combination value (α1 * A + α2 * B) includes the fifth filtering value (A) (α1 * A). Of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A), the value closer to “0” is determined as the basic value (No. 6). invention).

  In addition, in the sixth invention (fourth aspect), in other words, only the linear combination value calculating means is different from the fifth invention (third aspect), and the A in the linear combination value (α1 * A + α2 * B) is different. Instead of the lateral acceleration deviation, a fifth filtering value obtained by passing the lateral acceleration deviation through the fifth filter is used as the value of B, and the value of B in the linear combination value (α1 * A + α2 * B) is used. As a result, instead of the yaw angular acceleration deviation, a sixth filtering value obtained by passing the yaw angular acceleration deviation through the sixth filter is used.

  In these fifth and sixth inventions, as in the third and fourth inventions, the first term (α1 * A) in the linear combination value (α1 * A + α2 * B) is determined by the basic value determining means. The basic value as a value obtained by adjusting the lateral acceleration deviation (A) can be determined by reflecting the above-described polarity relationship between the first acceleration term and the second term (α1 * B). In the sixth aspect of the invention, instead of the lateral acceleration deviation itself, a fifth filtering value obtained by passing the lateral acceleration deviation through a fifth filter having a low cut characteristic is used, and instead of the yaw angle acceleration deviation itself. In addition, a sixth filtering value obtained by passing the yaw angular acceleration deviation through a sixth filter having a low cut characteristic is used. For this reason, when a steady offset component is included in the lateral acceleration deviation or the yaw angular acceleration deviation due to the drift of the output of the lateral acceleration sensor or the yaw angular acceleration detection sensor, the offset component Can be removed. For this reason, even when the lateral acceleration deviation or yaw angular acceleration deviation includes a steady offset component, the phenomenon relating to the polarity of the linear combination value and the polarity of each term of the linear combination value appears remarkably. Cheap. Therefore, the reliability of the basic value is increased.

  And in 5th invention and 6th invention, the correction | amendment calculating means of the side-slip movement state amount estimated value determination means uses the basic value determined as mentioned above, or the value which passed this basic value through the 4th filter which has a low cut characteristic. A value obtained by adding the corrected operation amount to the side-slip motion state amount model value is determined as an estimated value of the actual side-slip motion state amount of the vehicle.

  In this case, in the fifth and sixth aspects of the invention, the vehicle model calculation means calculates a new value of the side-slip motion state model value as a past calculation of the road reaction force model value and the estimated value of the side-slip motion state amount. Therefore, the estimated value of the skid motion state quantity as a value obtained by correcting the skid motion state model value is fed back to the process of sequentially calculating the skid motion state model value, and the skid motion state The quantity model value is calculated depending on the estimated value of the skid motion state. For this reason, in the calculation process of the side-slip motion state quantity model value in the vehicle model calculation means, the integration means (integration means that passes the lateral acceleration deviation) described with respect to the third and fourth inventions substantially reduces the skid motion state quantity. It will be included in the model value calculation process.

  Therefore, the basic value or a value obtained by passing the basic value through a fourth filter having a low cut characteristic is used as the correction operation amount, and a value obtained by adding the correction operation amount to the skid motion state amount model value is actually used. By determining the estimated value of the skid motion state quantity of the vehicle, the same effects as those of the third invention and the fourth invention can be obtained. That is, in a situation where the lateral acceleration deviation changes due to a change in the friction coefficient of the road surface or the movement state of the vehicle, the side slip movement state quantity model value is appropriately set according to the linear combination value or the lateral acceleration deviation. The corrected value can be determined as the estimated value of the skid motion state quantity, and the accuracy of the estimated value can be higher than the model value of the skid motion state quantity. Further, in a situation where the lateral acceleration deviation changes due to a change in the bank angle of the road surface, it is suppressed to correct the skid motion state quantity model value according to the lateral acceleration deviation, or Since the correction is not performed, the estimated value of the skid motion state amount fluctuates inappropriately from the actual value due to the change in the bank angle of the road surface that affects the lateral acceleration deviation. Thus, it is possible to prevent a situation that deviates from the actual value.

  In particular, in the sixth aspect of the invention, the influence can be eliminated even when a steady offset component is included in the lateral acceleration deviation or yaw angular acceleration deviation. Therefore, it is possible to prevent a situation in which the skid motion state quantity model value is inappropriately corrected due to a drift of the output of the lateral acceleration sensor or the yaw angular acceleration detection sensor. As a result, the accuracy and stability of the estimated value of the skid motion state quantity can be further increased.

  Further, when a value obtained by passing the basic value through a fourth filter having a low cut characteristic is used as the correction operation amount, due to a drift of an output of the lateral acceleration sensor or the yaw angular acceleration detection sensor, the In the case where a steady offset component is included in the basic value, it is possible to prevent such a situation that the side-slip motion state model value is inappropriately corrected by eliminating the influence thereof. As a result, the accuracy and stability of the estimated value of the skid motion state quantity can be further increased.

  Supplementally, in the fifth and sixth inventions, the fourth filter may be a filter having a high cut characteristic in addition to the low cut characteristic (that is, a bandpass filter). In the sixth invention, the fifth filter and the sixth filter may be filters having a high cut characteristic in addition to a low cut characteristic (that is, a band pass filter).

The figure which shows schematic structure of the vehicle in embodiment. 2A and 2B are diagrams visually showing typical reference symbols used in the description of the embodiment. The block diagram which shows the main functions of the control apparatus in 1st Embodiment. The flowchart which shows the process of the control apparatus in 1st Embodiment. The block diagram which shows the function of the vehicle model calculating means shown in FIG. 6A and 6B are graphs for explaining the processing of the wheel slip ratio estimation unit shown in FIG. 7A and 7B are graphs for explaining the processing of the wheel skid angle estimating unit shown in FIG. The graph for demonstrating the process of the other form of the wheel slip ratio estimation part shown in FIG. The flowchart which shows the process which calculates | requires the estimated value of the skid motion state amount of a vehicle in the vehicle motion estimation part shown in FIG. FIG. 10 is a block diagram showing the process of S114-5 in the flowchart of FIG. FIG. 4 is a block diagram showing functions of μ estimation means shown in FIG. 3. The flowchart which shows the process of the micro estimation means shown in FIG. FIG. 11 is a flowchart illustrating an example of processing instead of processing within a broken line frame in the block diagram of FIG. 10. The block diagram which shows the process of S114-5 of the flowchart of FIG. 9 in 2nd Embodiment. The block diagram which shows the main functions of the control apparatus in 3rd Embodiment. The flowchart which shows the process of the bank angle estimation means shown in FIG. The flowchart which shows the process of the gradient angle estimation means shown in FIG.

  Hereinafter, embodiments of the present invention will be described. First, a schematic configuration of a vehicle according to an embodiment of the present specification will be described with reference to FIG.

  As shown in FIG. 1, the vehicle 1 includes a plurality of wheels 2-i (i = 1, 2,...), And these wheels 2-i (i = 1, 2,. The vehicle body 1B is supported. More specifically, the vehicle 1 according to the embodiment includes a total of four wheels 2-i (i = 1, i.e., a pair of left and right front wheels 2-1 and 2-2 and a pair of left and right rear wheels 2-3 and 2-4. 2, 3, 4). In this case, the front wheels 2-1 and 2-2 of the wheels 2-i (i = 1, 2, 3, 4) are driving wheels and steering wheels, and the rear wheels 2-3, 2-4 are It is a non-steering wheel as well as a driven wheel.

  In the following explanation, the left front wheel 2-1 of the vehicle 1 is the first wheel 2-1, the right front wheel 2-2 is the second wheel 2-2, and the left rear wheel 2-3 is the third wheel. 2-3, the wheel 2-4 on the right rear side may be referred to as a fourth wheel 2-4. In addition, when expressing an arbitrary wheel of the wheels 2-i (i = 1, 2, 3, 4), a description such as “(i = 1, 2, 3, 4)” is omitted. May be simply referred to as “wheel 2-i” or “i-th wheel 2-i”. In addition, reference numerals of elements other than the wheels 2-i (i = 1, 2, 3, 4) (components, physical quantities, etc.) and related to the individual i-th wheels 2-i are subscripts “ i ”is added. In this case, for an element corresponding to a specific one of the wheels 2-i (i = 1, 2, 3, 4), instead of the subscript “i” in the reference numeral of the element, The value of i (1 or 2 or 3 or 4) corresponding to the specific wheel is added.

  The vehicle 1 is provided with a drive system for rotationally driving the drive wheels. In the embodiment, the drive system includes an engine 3 as a power generation source mounted on the vehicle body 1B. The drive system transmits the power (output torque) of the engine 3 to the front wheels 2-1 and 2-2 as drive wheels via the power transmission mechanism 4 including the transmission 4a, thereby causing the front wheels 2-1 to move. , 2-2 are rotated. In this case, the power of the engine 3 is controlled in accordance with a depression operation amount of an accelerator pedal (not shown) of the vehicle 1.

  The vehicle 1 is also provided with a steering system for steering the steered wheels. In this embodiment, the steering system includes a steering wheel 5 disposed in front of the driver's seat of the vehicle body 1B. The front wheel 2-1 as a steering wheel is operated by a steering mechanism (not shown) in conjunction with a rotation operation of the steering wheel 5. , 2-2 is steered. The steering mechanism is configured by a mechanical steering mechanism such as a rack and pinion, or a steering mechanism with an actuator having a steering actuator such as an electric motor (so-called power steering device).

  The vehicle 1 is also provided with a braking system for braking the running. In this embodiment, the braking system includes a frictional braking mechanism 7-i (i = 1, 2, 3, 4) such as a disc brake for each wheel 2-i. These braking mechanisms 7-i (i = 1, 2, 3, 4) are connected to a braking system hydraulic circuit 6, and depending on the hydraulic pressure (brake pressure) applied from the braking system hydraulic circuit 6, respectively. A braking force for braking the rotation of the corresponding wheel 2-i is generated. In this case, the braking system hydraulic circuit 6 basically applies the brake pressure corresponding to the depression amount (depression force) of the brake pedal in conjunction with the depression operation of the brake pedal (not shown) of the vehicle 1. Granted to mechanism 7-i. In the vehicle 1 according to the embodiment, the brake system hydraulic circuit 6 applies a brake pressure to be applied to each brake mechanism 7-i (and thus a brake force of each wheel 2-i) from the control device 20 described later. It is possible to adjust according to the control command.

  Furthermore, the vehicle 1 includes various sensors for detecting an observation target amount, which will be described later, and a control device 20 that performs behavior control of the vehicle 1 in addition to the drive system, the steering system, and the braking system. In the embodiment, as a sensor, for example, a wheel rotation angular velocity sensor 8-i (i = 1, 2, 3, 4) that generates an output corresponding to the rotation angular velocity of each wheel 2-i, and each wheel 2-i. A brake pressure sensor 9-i (i = 1, 2, 3, 4) for generating an output corresponding to the brake pressure applied to the brake mechanism 7-i, and a steering angle (rotation angle) of the steering wheel 5 Steering steering angle sensor 10 that generates output, transmission sensor 11 that generates output according to the operating state (gear ratio, etc.) of the transmission 3, output according to the amount of depression of an accelerator pedal (not shown) of the vehicle 1 Accelerator sensor 12 for generating the output, yaw rate sensor 13 for generating an output corresponding to the yaw rate that is the angular velocity around the yaw axis of the vehicle 1 (around the vertical axis of the vehicle body 1B), and the roll axis direction of the vehicle 1 (the vehicle body A longitudinal acceleration sensor 14 for generating an output corresponding to the acceleration in the direction B), and a lateral acceleration sensor 15 for generating an output corresponding to the acceleration in the pitch axis direction of the vehicle 1 (the lateral direction (left and right direction) of the vehicle body 1B). It is mounted on the vehicle 1.

  The control device 20 is an electronic circuit unit including a CPU, a RAM, a ROM, and the like, and outputs (detection data) of each sensor described above are input. Then, the control device 20 controls the behavior of the vehicle 1 by executing a predetermined calculation process based on a pre-installed program while using the input detection data and the setting data stored and held in advance. . In this case, the control device 20 controls the rotational force (turning motion) around the yaw axis of the vehicle 1 by controlling the braking force of each wheel 2-i by each braking mechanism 7-i via the braking system hydraulic circuit 6, for example. ) And side-slip motion, etc. Further, the control device 20 sequentially estimates the state quantity (side slip angle, side slip speed, etc.) of the skid motion of the vehicle 1 or executes the road 1 on which the vehicle 1 is traveling in order to execute the control process of the behavior of the vehicle 1. It also has a function of sequentially estimating the friction coefficient.

  The above is the schematic configuration of the vehicle 1 in each embodiment described in this specification.

  The vehicle to which the present invention is applied is not limited to the vehicle 1 having the above configuration. For example, the power generation source of the drive system of the vehicle 1 may be an electric motor. Alternatively, both the engine and the electric motor may be mounted on the vehicle 1 as power generation sources. Further, the drive wheels of the vehicle 1 may be the rear wheels 2-3, 2-4, or may be both the front wheels 2-1, 2-2 and the rear wheels 2-3, 2-4. Good. Further, the drive system may be configured such that the drive force applied to each drive wheel from the power generation source can be adjusted individually. In addition to steering the front wheels 2-1 and 2-2 in conjunction with the rotation operation of the steering wheel 5, the steering system of the vehicle 1 appropriately steers the rear wheels 2-3 and 2-4 by an actuator. It may be configured to. Further, the number of wheels may not be four.

  Next, with reference to FIGS. 2A and 2B, main reference symbols (variables) and terms used in the following description of each embodiment will be described.

  Variables prefixed with “↑”, such as ↑ V1, ↑ F1, etc. in FIGS. 2A and 2B, represent vector quantities. The vector quantity is expressed in the form of a column vector (transposition vector of row vector) when the component is displayed using an appropriate coordinate system. In the description of the embodiment, “×” is used as an arithmetic symbol for multiplication (ie, outer product) of vector quantities, and an arithmetic symbol for multiplication other than outer products, such as multiplication of scalar quantities or multiplication of a scalar quantity and a vector quantity. “*” Is used. Further, in order to indicate transposition of a row vector, the subscript “T” is added to the upper right of the component display of the row vector.

  The “vehicle body coordinate system” is a coordinate system in which the front-rear direction of the vehicle body 1B is the X-axis direction and the lateral direction (left-right direction) of the vehicle body 1B is the Y-axis direction. In this case, the forward direction of the vehicle body 1B is the positive direction of the X axis, and the left direction of the vehicle body 1B is the positive direction of the Y axis. Note that the X-axis direction of the vehicle body coordinate system may simply be the front-rear direction of the vehicle 1 or the roll axis direction. In addition, the Y-axis direction of the vehicle coordinate system may simply be the lateral direction or the pitch axis direction of the vehicle 1. Further, the yaw axis direction of the vehicle 1 (the vertical direction of the vehicle body 1B) is orthogonal to the XY plane of the vehicle body coordinate system (orthogonal to the X axis and the Y axis).

  The “i-th wheel coordinate system” is parallel to the rotation surface of the i-th wheel 2-i (a surface orthogonal to the rotation axis of the i-th wheel 2-i) when the vehicle 1 is viewed from above in the yaw axis direction. The direction (front-rear direction of the i-th wheel 2-i) is the x-axis direction, and the direction parallel to the rotation axis of the i-th wheel 2-i (the left-right direction (lateral direction) of the i-th wheel 2-i) is the y-axis. Coordinate system. In this case, the forward direction of the i-th wheel 2-i is the positive direction of the x-axis, and the left direction of the i-th wheel 2-i is the positive direction of the y-axis. It is assumed that the xy plane of the i-th wheel coordinate system is parallel to the XY plane of the vehicle body coordinate system and is orthogonal to the yaw axis direction of the vehicle 1.

  Supplementally, “orthogonal” and “parallel” in this specification do not mean only orthogonal or parallel in a strict sense, but may be approximate orthogonal or parallel.

  “Δi” represents the rudder angle of the i-th wheel 2-i (hereinafter, sometimes simply referred to as the wheel rudder angle). More specifically, each wheel rudder angle δi is an angle formed by the rotational surface of the i-th wheel 2-i with respect to the X-axis direction of the vehicle body coordinate system when the vehicle 1 is viewed from above in the yaw axis direction. In the vehicle 1 of the embodiment, since the rear wheels 2-3 and 2-4 are non-steering wheels, δ3 = δ4 = 0 is always satisfied.

  “↑ Vg” represents a moving speed vector (hereinafter referred to as a vehicle center-of-gravity speed vector) of the center of gravity of the vehicle 1 with respect to the road surface as viewed by projection onto the XY plane of the vehicle body coordinate system. The vehicle center-of-gravity velocity vector ↑ Vg is a vector composed of an X-axis direction component and a Y-axis direction component of the vehicle body coordinate system. In this case, the X-axis direction component of the vehicle center-of-gravity velocity vector ↑ Vg is expressed as Vgx, the Y-axis direction component is expressed as Vgy, and these are referred to as vehicle center-of-gravity longitudinal velocity Vgx and vehicle center-of-gravity skid velocity Vgy. In other words, the vehicle center-of-gravity longitudinal speed Vgx has a meaning as the traveling speed (vehicle speed) of the vehicle 1. Although not shown in FIGS. 2A and 2B, the temporal change rate (differential value) of the vehicle center-of-gravity longitudinal speed Vgx is the temporal change rate of the vehicle center-of-gravity longitudinal speed Vgdot_x and the vehicle center-of-gravity skid speed Vgy. The rate of change (differential value) is referred to as vehicle center-of-gravity skid speed change rate Vgdot_y.

“Βg” represents a side slip angle of the center of gravity of the vehicle 1 (hereinafter referred to as a vehicle center of gravity side slip angle). More specifically, the vehicle center-of-gravity skid angle βg is an angle formed by the vehicle center-of-gravity velocity vector ↑ Vg with respect to the X-axis direction of the vehicle body coordinate system. Therefore, βg = tan ⁻¹ (Vgy / Vgx).

  “↑ Vi” is a moving speed vector of the contact portion of the i-th wheel 2-i with respect to the road surface projected on the XY plane of the vehicle body coordinate system (hereinafter referred to as a traveling speed vector of the i-th wheel 2-i, or simply Wheel speed vector). Each wheel traveling speed vector ↑ Vi is a vector composed of an X-axis direction component and a Y-axis direction component of the vehicle body coordinate system. In this case, although not shown in FIGS. 2A and 2B, the X axis direction component of each wheel traveling speed vector ↑ Vi is expressed as Vx_i, and the Y axis direction component is expressed as Vy_i.

  “↑ Vsub_i” is a moving speed vector (hereinafter referred to as a wheel traveling speed vector on the wheel coordinate system) of the ground contact portion of the i-th wheel 2-i with respect to the road surface, as projected onto the xy plane of the i-th wheel coordinate system. Represent. The wheel traveling speed vector ↑ Vsub_i on each wheel coordinate system is a vector composed of the x-axis direction component and the y-axis direction component of the i-th wheel coordinate system. In this case, although illustration in FIGS. 2A and 2B is omitted, the x-axis direction component of the wheel traveling speed vector ↑ Vsub_i on each wheel coordinate system is denoted as Vsubx_i, and the y-axis direction component is denoted as Vsuby_i. The wheel traveling speed vector ↑ Vsub_i on the wheel coordinate system of each wheel 2-i and the wheel traveling speed vector ↑ Vi differ only in the coordinate system representing them, and the spatial orientation and size are different. They are the same vector quantity.

“Βi” represents the side slip angle of the i-th wheel 2-i (hereinafter, simply referred to as the wheel side slip angle). More specifically, each wheel side slip angle βi is an angle formed by the wheel traveling speed vector ↑ Vsub_i on the wheel coordinate system of the i-th wheel 2-i with respect to the x-axis direction of the i-th wheel coordinate system. Therefore, βi = tan ⁻¹ (Vsuby_i / Vsubx_i).

  “Β0i” represents an angle (= βi + δi, hereinafter referred to as a wheel position side slip angle) formed by the wheel traveling speed vector ↑ Vi of the i-th wheel 2-i with respect to the X-axis direction of the vehicle body coordinate system. In the embodiment, since the rear wheels 2-3 and 2-4 are non-steering wheels, β03 = β3 and β04 = β4. For this reason, illustration of β03 and β04 is omitted.

  “Γ” represents an angular velocity around the yaw axis of the vehicle 1, that is, a yaw rate.

  “Df” is the distance between the front wheels 2-1 and 2-2 in the lateral direction of the vehicle 1 (Y-axis direction of the vehicle body coordinate system) (that is, the tread of the front wheels 2-1 and 2-2), and “dr” is the vehicle 1 represents the distance between the rear wheels 2-3 and 2-4 in the horizontal direction (Y-axis direction of the vehicle body coordinate system) (that is, the tread of the rear wheels 2-3 and 2-4). Hereinafter, df is referred to as a front wheel tread, and dr is referred to as a rear wheel tread.

  “Lf” is the distance between the axles (rotating shafts) of the front wheels 2-1 and 2-2 in the state where δ1 = δ2 = 0 and the center of gravity of the vehicle 1 (distance in the front-rear direction of the vehicle 1), “ Lr ″ represents the distance between the axle (rotary axis) of the rear wheels 2-3 and 2-4 and the center of gravity of the vehicle 1 (the distance in the front-rear direction of the vehicle 1). Hereinafter, Lf is referred to as the distance between the front wheel axle and the center of gravity, and Lr is referred to as the distance between the rear wheel axle and the center of gravity.

“↑ Pi” is a position vector of the i-th wheel 2-i viewed from the center of gravity of the vehicle 1 in a state where the vehicle 1 is viewed from above in the yaw axis direction (hereinafter, sometimes simply referred to as a wheel position vector). Represent. Each wheel position vector ↑ Pi is a vector composed of an X-axis direction component and a Y-axis direction component of the vehicle body coordinate system. In this case, although not shown in FIGS. 2A and 2B, the X-axis direction component of each wheel position vector ↑ Pi is expressed as Px_i, and the Y-axis direction component is expressed as Py_i. When the position of the center of gravity of the vehicle 1 in the Y-axis direction of the vehicle body coordinate system is on the center line of the vehicle width of the vehicle 1, ↑ P1 = (Lf, df / 2) ^T , ↑ P2 = (Lf, −df / 2) ^T , ↑ P3 = (− Lr, dr / 2) ^T , ↑ P4 = (− Lr, −dr / 2) ^T

  “↑ Fi” represents the road surface reaction force of the i-th wheel 2-i (translational force vector acting on the i-th wheel 2-i from the road surface) as projected on the XY plane of the vehicle body coordinate system. Hereinafter, ↑ Fi is referred to as a wheel two-dimensional road surface reaction force or a two-dimensional road surface reaction force. This wheel two-dimensional road surface reaction force ↑ Fi is a vector composed of an X-axis direction component and a Y-axis direction component of the vehicle body coordinate system. Here, the road surface reaction force acting on each wheel 2-i from the road surface spatially (three-dimensionally) is a driving / braking force that is a translational force component in the x-axis direction of the i-th wheel coordinate system, and y It is a resultant vector of lateral force, which is a translational force component in the axial direction, and ground contact load, which is a translational force component in the yaw axis direction. Accordingly, the wheel two-dimensional road surface reaction force ↑ Fi is a resultant vector of the driving / braking force and lateral force of the i-th wheel 2-i (this corresponds to a friction force acting on the i-th wheel 2-i from the road surface). Is a vector that is expressed in the vehicle body coordinate system. In this case, although illustration in FIGS. 2A and 2B is omitted, the X-axis direction component of the wheel two-dimensional road surface reaction force ↑ Fi is expressed as Fx_i, and the Y-axis direction component is expressed as Fy_i. In the following description, the spatial road surface reaction force as a resultant vector of the driving / braking force, lateral force, and contact load of each wheel 2-i is referred to as a wheel three-dimensional road surface reaction force or a three-dimensional road surface reaction force. . Moreover, the ground contact load as a yaw-axis direction component of the three-dimensional road surface reaction force of each wheel 2-i is described as Fz_i.

  “↑ Fsub_i” represents the road surface reaction force of the i-th wheel 2-i projected on the xy plane of the i-th wheel coordinate system (hereinafter referred to as a wheel coordinate system upper wheel two-dimensional road surface reaction force). Each wheel coordinate system upper wheel two-dimensional road surface reaction force ↑ Fsub_i is a vector composed of an x-axis direction component and a y-axis direction component of the i-th wheel coordinate system. In this case, although illustration in FIGS. 2A and 2B is omitted, the x-axis direction component of each wheel coordinate system upper wheel two-dimensional road surface reaction force ↑ Fsub_i is represented as Fsubx_i, and the y-axis direction component is represented as Fsuby_i. . In other words, the x-axis direction component Fsubx_i is the driving / braking force of the i-th wheel 2-i, and the y-axis direction component Fsuby_i is the lateral force of the i-th wheel 2-i. The wheel coordinate system upper wheel two-dimensional road surface reaction force ↑ Fsub_i of the i-th wheel 2-i and the wheel two-dimensional road surface reaction force ↑ Fi of the i-th wheel 2-i are different in the coordinate system expressing them. These are vector quantities having the same spatial orientation and size.

  “↑ Fg_total” is the resultant force of the road surface reaction force acting on the wheel 2-i (i = 1, 2, 3, 4) (the resultant force of the wheel three-dimensional road surface reaction force (i = 1, 2, 3, 4)) ) Represents a spatial translation force vector (hereinafter referred to as a total road surface reaction force synthesis translation force vector) acting on the center of gravity of the vehicle 1. In this case, although illustration in FIGS. 2A and 2B is omitted, the X-axis direction component of the vehicle body coordinate system of the total road surface reaction force combined translation force vector ↑ Fg_total is Fgx_total, and Y of the vehicle body coordinate system The axial direction component is expressed as Fgy_total, and the yaw axis direction component is expressed as Fgz_total. Also, Fgx_total may be referred to as total road reaction force combined longitudinal force, and Fgy_total may be referred to as total road reaction force combined lateral force.

  “Mgz_total” is the resultant of the road surface reaction force acting on the wheel 2-i (i = 1, 2, 3, 4) (the i-th wheel three-dimensional road surface reaction force (i = 1, 2, 3, 4)). The resultant force represents a moment acting around the yaw axis at the center of gravity of the vehicle 1 (hereinafter referred to as a total road surface reaction force combined yaw moment). The yaw axis direction component Fgz_total of the resultant force of the wheel three-dimensional road surface reaction force (i = 1, 2, 3, 4) does not contribute to the total road surface reaction force combined yaw moment Mgz_total. Therefore, the total road surface reaction force combined yaw moment Mgz_total is substantially equal to the resultant force of the wheel two-dimensional road surface reaction force ↑ Fi (i = 1, 2, 3, 4), that is, all the wheels 2-i (i = 1, 2, 3, 4) represents the moment acting around the yaw axis at the center of gravity of the vehicle 1 by the resultant force of driving / braking force and lateral force.

  Supplementally, in the embodiment of the present specification, the resultant force of the road surface reaction force acting on the wheel 2-i (i = 1, 2, 3, 4) is regarded as the entire external force acting on the vehicle 1. More specifically, the external force acting on the vehicle 1 includes air resistance and the like in addition to the road surface reaction force acting on each wheel 2-i from the road surface, but in the embodiment, the external force other than the road surface reaction force is: Compared to the resultant force of the road surface reaction force acting on the wheel 2-i (i = 1, 2, 3, 4), it is considered to be sufficiently small to be negligible. Therefore, ↑ Fg_total and Mgz_total have meanings as a translational force vector and a moment acting on the center of gravity of the vehicle 1 due to the entire external force acting on the vehicle 1, respectively.

  “NSP” represents the neutral steer point of the vehicle 1. When the vehicle 1 is traveling with δ1 = δ2 = 0 and the vehicle center-of-gravity skid angle βg (≠ 0) is generated, the NSP generates all wheels 2-i (i = 1, 2, 3, 4). ) Means the point of application (action point) of the resultant force of the lateral force Fsuby_i (i = 1, 2, 3, 4). More specifically, the NSP has a straight line extending in the X-axis direction of the vehicle body coordinate system (the front-rear direction of the vehicle 1) through the center of gravity of the vehicle 1 when the vehicle 1 is viewed from above in the yaw axis direction. It means the intersection with the action line of the resultant force of the lateral force Fsuby_i (i = 1, 2, 3, 4) acting on all the wheels 2-i (i = 1, 2, 3, 4), respectively.

  “Lnsp” represents the distance between the center of gravity of the vehicle 1 and the NSP in the X-axis direction (the front-rear direction of the vehicle 1) of the vehicle body coordinate system (hereinafter referred to as the vehicle center-of-gravity / distance between NSPs). When the NSP exists behind the center of gravity of the vehicle 1, the vehicle center-NSP distance Lnsp is set to a positive value, and the NSP exists ahead of the center of gravity of the vehicle 1. The vehicle center of gravity / NSP distance Lnsp is set to a negative value.

  “Mnsp” is the resultant force of the road surface reaction force acting on the wheel 2-i (i = 1, 2, 3, 4) (the resultant force of the wheel three-dimensional road surface reaction force (i = 1, 2, 3, 4) or By the wheel two-dimensional road surface reaction force ↑ Fi (the resultant force of i = 1, 2, 3, 4), a moment acting around the yaw axis by NSP (hereinafter referred to as NSP yaw moment) is represented. In other words, the NSP yaw moment Mnsp is the sum of the total road surface reaction force combined yaw moment Mgz_total and the total road surface reaction force combined translational force vector ↑ Fg_total generated around the yaw axis by the NSP (= Lnsp * Fgy_total). Moment.

  Supplementally, in the embodiment, state quantities (δi, βi, γ, etc.) related to rotational movement around the yaw axis, such as angles, angular velocities, angular accelerations around the yaw axis, and moments (Mgz_total, Mnsp, etc.) around the yaw axis, With respect to, in the state where the vehicle 1 is viewed from above in the yaw axis direction, the counterclockwise direction is defined as a positive direction.

  Although not shown in FIGS. 2A and 2B, the following variables are used in the following description in addition to the variables (reference numerals) described above.

  “Θh” represents the steering angle (rotation angle; hereinafter referred to as the steering angle) of the steering wheel 5.

  “Γdot” represents angular acceleration around the yaw axis of the vehicle 1 (hereinafter referred to as yaw angular acceleration). The yaw axis is a yaw axis that passes through the center of gravity of the vehicle 1.

  “Ωw_i” may be referred to as the rotational angular velocity of the i-th wheel 2-i (hereinafter, simply referred to as wheel rotational angular velocity), and “Rw_i” may be referred to as the effective radius of the i-th wheel 2-i (hereinafter simply referred to as effective wheel radius). ), “Vw_i” is the wheel speed of the i-th wheel 2-i defined as the product of ωw_i and Rw_i (= ωw_i * Rw_i) (that is, i-th viewed from the rotation center of the i-th wheel 2-i). (Circumferential speed of the ground contact portion of the wheel 2-i). Each wheel speed Vw_i matches the x-axis direction component Vsubx_i of the wheel traveling speed vector ↑ Vsub_i on the wheel coordinate system in a state where the i-th wheel 2-i is not slipped.

  “Κi” is a slip ratio of the i-th wheel 2-i (longitudinal slip ratio; hereinafter, simply referred to as a wheel slip ratio), and “Tq_i” is given to the i-th wheel 2-i from the drive system of the vehicle 1. The total torque of the driving torque and the braking torque applied from the braking system of the vehicle 1 (hereinafter simply referred to as wheel torque), “Iw_i” is the moment of inertia of the i-th wheel 2-i (hereinafter simply referred to as the wheel). Inertia moment).

  “M” represents the mass of the entire vehicle 1 (hereinafter referred to as vehicle mass), and “Iz” represents the moment of inertia around the yaw axis of the entire vehicle 1 at the center of gravity of the vehicle 1 (hereinafter referred to as vehicle yaw inertia moment).

  “Accx” is the X-axis direction component of the vehicle body coordinate system of the acceleration generated at the center of gravity of the vehicle 1 due to the centrifugal force accompanying the turning motion of the vehicle 1 (= -Vgy * γ) is added to represent the acceleration (= Vgdot_x−Vgy * γ). Further, “Accy” is the Y axis direction component of the vehicle body coordinate system of the acceleration generated at the center of gravity of the vehicle 1 due to the centrifugal force accompanying the turning motion of the vehicle 1 to the vehicle center of gravity side slip velocity change rate Vgdot_y. Acceleration (= Vgdot_y + Vgx * γ) obtained by adding (= Vgx * γ). In other words, “Accx” and “Accy” are respectively the X-axis directions of the acceleration of the motion of the center of gravity of the vehicle 1 as viewed in the vehicle body coordinate system (the second derivative of the position of the center of gravity in the vehicle body coordinate system). Component, Y-axis direction component. Hereinafter, “Accx” is referred to as vehicle center-of-gravity longitudinal acceleration, and “Accy” is referred to as vehicle center-of-gravity lateral acceleration.

  “Μ” represents a friction coefficient of the road surface (a friction coefficient between the wheels 2-i. Hereinafter, it may be referred to as a road surface friction coefficient). In the embodiment, the road surface friction coefficient μ is a relative value based on a friction coefficient between a road surface in a certain reference state (hereinafter referred to as a reference road surface) such as a standard dry road surface and each wheel 2-i. It is a coefficient of friction. Further, it is considered that the road surface friction coefficient μ is the same at the contact point of any wheel 2-i (i = 1, 2, 3, 4).

  “Θbank” represents a road bank angle (hereinafter, sometimes referred to as a road surface bank angle), and “θslope” represents a road surface slope angle (hereinafter, sometimes referred to as a road surface gradient angle). The road surface bank angle θbank is an inclination angle of the road surface with respect to the horizontal plane as viewed in the roll axis direction of the vehicle 1, and the road surface gradient angle θslope is an inclination angle of the road surface with respect to the horizontal plane as viewed in the pitch axis direction of the vehicle 1. The road surface bank angle θbank is generally referred to as a road surface cant angle in the field of automotive engineering, but the term bank angle is used in this specification. In the embodiment of the present specification, the road bank angle θbank when the vehicle 1 on the road surface is inclined to the right is assumed to be a positive angle. Further, the road surface slope angle θslope when the vehicle 1 on the road surface is in a forward-declining inclination posture is set as a positive angle.

“Rot (δi)” is a vector quantity (vector quantity consisting of an x-axis direction component and a y-axis direction component of the i-th wheel coordinate system) expressed in the i-th wheel coordinate system, expressed in the vehicle body coordinate system ( This represents a coordinate conversion matrix for conversion into a vector quantity consisting of an X-axis direction component and a Y-axis direction component of the vehicle body coordinate system. The coordinate transformation matrix R (δi) is a matrix (second-order square matrix) determined depending on the steering angle δi of the i-th wheel 2-i, and a column vector (cos (δi), sin (δi)) ^T , (−sin (δi), cos (δi)) A matrix in which ^T is a component in the first column and a component in the second column, respectively. In this case, if the notation of a vector quantity ↑ A in the i-th wheel coordinate system is (ax, ay) ^T and the notation in the vehicle body coordinate system is (Ax, Ay) ^T , (Ax, Ay) ^T and (ax , the relationship between the ay) ^T is a ^{(Ax, Ay) T = Rot} (δi) * (ax, ay) T. Therefore, the relationship between the wheel traveling speed vector ↑ Vi of each wheel 2-i and the wheel traveling speed vector ↑ Vsub_i on the wheel coordinate system is given by ↑ Vi = Rot (δi) * ↑ Vsub_i. Similarly, the relationship between the wheel two-dimensional road surface reaction force ↑ Fi of each wheel 2-i and the wheel coordinate system upper wheel two-dimensional road surface reaction force ↑ Fsub_i is represented by ↑ Fi = Rot (δi) * ↑ Fsub_i. Given. A coordinate transformation matrix for converting a vector quantity expressed in the vehicle body coordinate system into a vector quantity expressed in the i-th wheel coordinate system, that is, an inverse matrix of Rot (δi) is Rot (−δi).

  In the following description, when expressing an actual value (true value) state quantity, vector quantity, etc., the head of the name (name) of the state quantity, vector quantity, etc., such as “actual yaw rate”, etc. May be marked with "real". In this case, “_act” is added to the end of a variable (reference code) representing the state quantity, vector quantity, etc., such as “γ_act”. Furthermore, when expressing an observed value (detected value or estimated value) of a state quantity or vector quantity, the name of the state quantity or vector quantity (for example, “yaw rate detected value”, “yaw rate estimated value”, etc.) "Detected value" or "estimated value" is added to the end of the name. In this case, in principle, an “estimated value” is used for an observed value calculated by the vehicle model calculating means 24 described later or another observed value generated based on the calculated observed value. However, it is an observation value calculated by dynamic calculation (calculation of a dynamic model expressing vehicle dynamics) in the vehicle model calculation means 24, and each calculation process is performed by appropriately modifying the observation value. An observed value for which a final “estimated value” in a cycle is determined is referred to as a “model estimated value” in order to distinguish it from the final “estimated value”. Further, the “detected value” is used for the observed value obtained based on the output of a certain sensor without using the observed value calculated by the vehicle model calculating means 24. “Detected value” is appended with “_sens” at the end of the variable (reference sign) such as “γ_sens”, and “estimated value” is a variable (referenced) such as “γ_estm”. Add "_estm" to the end of the sign. Further, “_predict” is added to the end of the variable (reference code), such as “γ_predict”, for the “model estimated value”. Further, when expressing a temporal change rate (differential value depending on time) of a state quantity, “dot” is added to a variable (reference code) of the state quantity, such as “γdot”.

  Based on the above description, embodiments of the present invention will be described in detail below.

[First Embodiment]
First, the process of the control device 20 in the first embodiment will be specifically described. In the present embodiment, as shown in the block diagram of FIG. 3, the control device 20 includes an observation target amount detection means 22, a vehicle model calculation means 24, and a μ estimation means 26 as its main functional means.

  The observation target amount detection means 22 executes a process of detecting a predetermined type of observation target amount related to the behavior of the vehicle 1 from the outputs (detection data) of the various sensors of the vehicle 1 and obtains the detected value of the observation target amount. Means for generating.

  In the present embodiment, the observation target quantity by the observation target quantity detection means 22 includes the actual steering angles δ1_act and δ2_act of the steered wheels (front wheels) 2-1 and 2-2 and the actual wheel speed Vw_i_act (i = 1, 2, 3, 4), the actual yaw rate γ_act and actual yaw angular acceleration γdot_act of the vehicle 1, the actual vehicle center-of-gravity longitudinal acceleration Accx_act, the actual vehicle center-of-gravity lateral acceleration Accy_act, and the actual wheel torque Tq_i_act (i = 1, 2, 3, 4). And are included.

  In order to generate detection values of these observation target amounts, the observation target amount detection means 22 includes wheel steering angle detection means 22a for generating wheel steering angle detection values δ1_sens and δ2_sens of the front wheels 2-1, 2-2, Wheel speed detection means 22b for generating wheel speed detection value Vw_i_sens (i = 1, 2, 3, 4), yaw rate detection means 22c for generating yaw rate detection value γ_sens, and yaw angle for generating yaw angular acceleration detection value γdot_sens Acceleration detection means 22d, longitudinal acceleration detection means 22e for generating vehicle center-of-gravity longitudinal acceleration detection value Accx_sens, lateral acceleration detection means 22f for generating vehicle center-of-gravity lateral acceleration detection value Accy_sens, and wheel torque detection value Tq_i_sens (i = 1, 2, 3, 4) for generating wheel torque detection means 22 g.

  The vehicle model calculation means 24 includes a friction characteristic model that expresses the relationship between the slip between each wheel 2-i and the road surface and the road surface reaction force acting on the wheel 2-i from the road surface, and the external force acting on the vehicle 1. Road surface reaction force acting on each wheel 2-i using a dynamic model of the vehicle 1 (hereinafter, simply referred to as a vehicle model) including a vehicle motion model that expresses a relationship between the vehicle 1 and the motion of the vehicle 1 And a process for estimating a state quantity of motion of the vehicle 1 that is dynamically generated by the road surface reaction force acting on the vehicle 1 as an external force. For this process, the vehicle model calculation unit 24 detects the detection values of the predetermined types of observation target amounts generated by the observation target amount detection unit 22 (in this embodiment, δ1_sens, δ2_sens, Vw_i_sens, γ_sens, γdot_sens, Accy_sens). , Accy_sens, Tq_i_sens) and the latest road surface friction coefficient estimated value μ_estm already determined by the μ estimating means 26 are input. And the vehicle model calculating means 24 estimates the road surface reaction force of each wheel 2-i and the state quantity of the motion of the vehicle 1 using these input values and the vehicle model. Note that the vehicle model calculation means 24 is a vehicle that has already been obtained in the past calculation processing cycle, in addition to the above input values, in order to estimate the road surface reaction force of each wheel 2-i and the state quantity of the movement of the vehicle 1. The estimated value (including the model estimated value) of the state quantity of one motion is also used.

  The estimated value obtained by the vehicle model calculating means 24 includes a road surface reaction force estimated value that is an estimated value regarding the road surface reaction force, a translational motion of the vehicle 1 in the front-rear direction (roll axis direction) and the lateral direction (pitch axis direction), and These are roughly classified into vehicle motion state quantity estimated values, which are estimated values (including model estimated values) of state quantities related to rotational motion around the yaw axis.

  In this case, the road surface reaction force estimated value includes an estimated value of the driving / braking force Fsubx_i and lateral force Fsuby_i of each wheel 2-i and an estimated value of the ground load Fz_i, and a total road surface reaction force combined translational force vector. The estimated value ↑ Fg_total_estm (Fgx_total_estm and Fgy_total_estm) and the total road surface reaction force combined yaw moment estimated value Mgz_total_estm are included. Further, the vehicle motion state amount estimated value includes a yaw rate estimated value γ_estm, a vehicle center-of-gravity longitudinal speed estimated value Vgx_estm, a vehicle center-of-gravity skid speed estimated value Vgy_estm, a vehicle center-of-gravity skid speed model estimated value Vgy_predict, and the like. In this case, in this embodiment, more specifically, with respect to the yaw rate γ, the vehicle center-of-gravity longitudinal speed Vgx, and the vehicle center-of-gravity skid speed Vgy, model estimates are calculated and the respective model estimates are corrected as appropriate. The final estimated value in each arithmetic processing cycle is determined. However, regarding the yaw rate γ, the model estimated value γ_predict and the final estimated value γ_estm are determined so as to coincide with or substantially coincide with the yaw rate detected value γ_sens (do not deviate from γ_sens). Similarly, with respect to the vehicle center-of-gravity longitudinal speed Vgx, the model estimated value Vgx__predict and the final estimated value Vgx_estm coincide with or substantially coincide with a later-described wheel speed selection detection value Vw_i_sens_select as a detection value of the vehicle speed (does not deviate from Vw_i_sens_select). ) To be determined.

  The μ estimation means 26 is a means for executing processing for estimating the friction coefficient μ (road surface friction coefficient μ) of the road surface on which the vehicle 1 is traveling. For this processing, the μ estimation means 26 calculates δ1_sens, δ2_sens, γ_sens, γdot_sens, Accy_sens among the detection values of the observation target amount generated by the observation target amount detection means 22 and the vehicle model calculation means 24. Total road surface reaction force combined translation force vector estimated value ↑ Fg_total_estm (more specifically, all road surface reaction force combined lateral force estimated value Fgy_total_estm of ↑ Fg_total_estm) and total road surface reaction force combined yaw moment estimated value Mgz_total_estm, and vehicle model The vehicle center-of-gravity center longitudinal speed estimated value Vgx_estm among the vehicle motion state amount estimated values calculated by the computing means 24 is input. Then, the μ estimation means 26 calculates a road surface friction coefficient estimated value μ_estm that is an estimated value of the road surface friction coefficient μ using these input values.

  The control device 20 sequentially executes the processing shown in the flowchart of FIG. 4 at a predetermined calculation processing cycle by the observation target amount detection unit 22, the vehicle model calculation unit 24, and the μ estimation unit 26. In the following description, the values (detected values, estimated values, etc.) obtained in the current (current) computation processing cycle of the control device 20 and the previous (previous) computation processing cycle are obtained. In order to distinguish between values, the former may be referred to as “current value” and the latter as “previous value”. Then, a suffix “_p” is added to the reference sign of the previous value, for example, “γ_estm_p”. In this case, “previous value” means the latest value among the values already obtained in the past calculation processing cycle of the control device 20. A value that does not particularly refer to “current value” and “previous value” means the current value.

  Referring to FIG. 4, control device 20 first executes the process of observation target amount detection means 22 in S100. The observation target amount detection means 22 includes a wheel rotation angular velocity sensor 8-i (i = 1, 2, 3, 4), a brake pressure sensor 9-i (i = 1, 2, 3, 4), a steering steering angle. From the outputs of various sensors such as the sensor 10, the transmission sensor 11, the accelerator sensor 12, the yaw rate sensor 13, the longitudinal acceleration sensor 14, and the lateral acceleration sensor 15, the detected values δ1_sens, δ2_sens, Vw_i_sens (i = 1, 2) , 3, 4), γ_sens, γdot_sens, Accy_sens, Accy_sens, and Tq_i_sens.

  More specifically, the wheel steering angle detection values δ1_sens and δ2_sens are generated from the output of the steering steering angle sensor 10 by the wheel steering angle detection means 22a. Here, in the present embodiment, the actual rudder angle δ1_act of the first wheel 2-1 and the actual rudder angle δ2_act of the second wheel 2-2 are the same as each other, and hence δ1_sens = δ2_sens. Therefore, hereinafter, the steering angles δ1 and δ2 of the front wheels 2-1 and 2-2 are generically referred to as front wheel steering angles δf, and the wheel steering angle detection values δ1_sens and δ2_sens are generically referred to as front wheel steering angle detection values δf_sens. Then, the wheel steering angle detection means 22a calculates the steering steering angle θh and the front wheel steering angle δf from the steering steering angle detection value θh_sens which is a steering steering angle value (converted value) indicated by the output value of the steering steering angle sensor 10. A front wheel steering angle detection value δf_sens (= δ1_sens = δ2_sens) as a common steering angle detection value of the front wheels 2-1 and 2-2 is obtained based on a preset relationship (model, map, etc.).

  For example, when the steering mechanism of the vehicle 1 is configured such that the actual steering angles δ1_act and δ2_act of the front wheels 2-1 and 2-2 are substantially proportional to the actual steering steering angle θh_act, a proportional constant set in advance to θh_sens. Δf_sens is calculated by multiplying (so-called overall steering ratio).

  When the steering mechanism includes a steering actuator such as a power steering device, in addition to the steering steering angle detection value θh_sens or instead of the steering steering angle detection value θh_sens, It is also possible to detect the operating state of the actuator or the state quantity that defines it, and use the detected value to determine the detected front wheel steering angle value Δf_sens.

  Further, the steering angle detection values δ1_sens and δ2_sens of the front wheels 2-1 and 2-2 may be individually obtained by using a stricter steering system model or the like. The average value (= (δ1_sens + δ2_sens) / 2) of the detected steering angle values δ1_sens and δ2_sens of the front wheels 2-1 and 2-2 is representative of the actual steering angles δ1_act and δ2_act of the front wheels 2-1 and 2-2. You may make it obtain | require as the front-wheel steering angle detected value (delta) f_sens to do.

  The wheel speed detection value Vw_i_sens (i = 1, 2, 3, 4) is generated by the wheel speed detection means 22b from the output of the corresponding wheel rotation angular velocity sensor 8-i. Specifically, for each wheel 2-i, the wheel speed detection means 22b sets a wheel rotation angular velocity detection value ωw_i_sens that is an angular acceleration value (converted value) indicated by an output value of the wheel rotation angular velocity sensor 8-i. The wheel speed detection value Vw_i_sens is obtained by multiplying the value of the effective radius Rw_i of the i-th wheel 2-i set in advance.

  The yaw rate detection value γ_sens and the yaw angular acceleration detection value γdot_sens are respectively generated from the output of the yaw rate sensor 13 by the yaw rate detection means 22c and the yaw angular acceleration detection means 22d. That is, the yaw rate detection means 22c generates the angular velocity value (converted value) indicated by the output value of the yaw rate sensor 13 as the yaw rate detection value γ_sens. Further, the yaw angular acceleration detection means 22d differentiates the yaw rate detection value γ_sens (determines the temporal change rate) or the value of the angular acceleration indicated by the value obtained by differentiating the output value of the yaw rate sensor 13 ( Conversion value) is generated as the detected yaw angular acceleration value γdot_sens.

  Note that the yaw angular acceleration detection value γdot_sens can be generated from the output of a sensor different from the yaw rate sensor 13. For example, two acceleration sensors are mounted on the vehicle body 1B with a gap Lacc in a direction orthogonal to the yaw axis direction of the vehicle 1 (for example, the roll axis direction or the pitch axis direction of the vehicle 1). In this case, these two acceleration sensors are arranged so as to be sensitive to acceleration in a direction orthogonal to the interval direction of the two acceleration sensors and the yaw axis direction. In this case, the yaw angular acceleration detection value γdot_sens can be generated by dividing the difference between the acceleration detection values indicated by the output values of the two acceleration sensors by the interval Lacc.

  The vehicle center-of-gravity longitudinal acceleration detection value Accx_sens is generated from the output of the longitudinal acceleration sensor 14 by the longitudinal acceleration detection means 22e. Further, the vehicle center-of-gravity lateral acceleration detection value Accy_sens is generated from the output of the lateral acceleration sensor 15 by the lateral acceleration detection means 22f. Here, in the present embodiment, the position of the center of gravity of the vehicle 1 is specified in advance, and the longitudinal acceleration sensor 14 and the lateral acceleration sensor 15 are fixed to the vehicle body 1B so as to be positioned at the center of gravity. The longitudinal acceleration sensor 14 and the lateral acceleration sensor 15 may be an integral structure acceleration sensor (biaxial acceleration sensor).

  Then, the longitudinal acceleration detection means 22e generates the acceleration value (converted value) indicated by the output value of the longitudinal acceleration sensor 14 as the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens. Further, the lateral acceleration detection means 22f generates an acceleration value (converted value) indicated by the output value of the lateral acceleration sensor 15 as a vehicle center-of-gravity lateral acceleration detection value Accy_sens.

  Even when the longitudinal acceleration sensor 14 or the lateral acceleration sensor 15 is arranged at a position shifted from the center of gravity of the vehicle 1, the acceleration detection value indicated by the output value of the sensor 14 or 15 is used as the yaw angular acceleration detection. By correcting according to the value γdot_sens (or the differential value of the yaw rate detection value γ_sens), the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens or the vehicle center-of-gravity lateral acceleration detection value Accy_sens can be generated. For example, in the case where the longitudinal acceleration sensor 14 is arranged at a position having a Ly interval on the left side from the center of gravity of the vehicle 1, an acceleration detection value (acceleration at the position of the sensor 14) indicated by the output value of the longitudinal acceleration sensor 14. The vehicle center-of-gravity longitudinal acceleration detection value Accx_sens can be generated by adding the value obtained by multiplying the yaw angular acceleration detection value γdot_sens (or the differential value of the yaw rate detection value γ_sens) by Ly. Similarly, when the lateral acceleration sensor 15 is disposed at a position having a distance Lx forward from the center of gravity of the vehicle 1, the acceleration detection value (the position of the sensor 15 is indicated by the output value of the lateral acceleration sensor 15). The vehicle center-of-gravity lateral acceleration detected value Accy_sens can be generated by subtracting the value obtained by multiplying the detected yaw angular acceleration value γdot_sens (or the differential value of the yaw rate detected value γ_sens) by Lx from the detected acceleration value.

  Supplementally, the acceleration detected (sensitive) by the longitudinal acceleration sensor 14 is an acceleration vector generated at the center of gravity of the vehicle 1 by the entire external force acting on the vehicle 1 (the resultant force) (the center of gravity of the vehicle 1 by the entire external force). Of the acceleration vector obtained by dividing the acting translational force vector by the vehicle mass m), it has a meaning as a longitudinal component of the vehicle body 1B (X-axis direction component of the vehicle body coordinate system). In this case, the acceleration to which the longitudinal acceleration sensor 14 is sensitive is the actual vehicle center-of-gravity longitudinal acceleration Accx_act as an original detection target if the actual road surface slope angle θslope_act is “0”. On the other hand, when the actual road surface gradient angle θslope_act is not “0”, the longitudinal direction (X-axis direction) of the vehicle body 1B, which is the sensitive direction of the longitudinal acceleration sensor 14, has an inclination of θslope_act with respect to the horizontal plane. . For this reason, the longitudinal acceleration sensor 14 includes not only the actual vehicle center-of-gravity longitudinal acceleration Accx_act but also the acceleration component in the direction parallel to the longitudinal direction of the vehicle body 1B (= −g * sin (θslope_act). It is also sensitive to acceleration constant. Therefore, the vehicle center-of-gravity longitudinal acceleration detected value Accx_sens as the acceleration indicated by the output of the longitudinal acceleration sensor 14 is actually the actual vehicle center-of-gravity longitudinal acceleration Accx_act in the direction parallel to the longitudinal direction of the vehicle body 1B of the gravitational acceleration. This is the detected value of acceleration (= Accx_act−g * sin (θslope_act)) formed by superimposing the acceleration component (including the case of θslope_act = 0).

  Similarly to the above, the acceleration detected (sensitive) by the lateral acceleration sensor 15 is the acceleration vector generated in the center of gravity of the vehicle 1 due to the entire external force acting on the vehicle 1 (the resultant force) in the lateral direction of the vehicle body 1B. It has meaning as a component (Y-axis direction component of the vehicle body coordinate system). In this case, the acceleration to which the lateral acceleration sensor 15 is sensitive is the actual vehicle center-of-gravity lateral acceleration Acty_act as an original detection target if the actual road bank angle θbank_act is “0”. On the other hand, when the actual road surface bank angle θbank_act is not “0”, the lateral direction (Y-axis direction) of the vehicle body 1B that is the sensitive direction of the lateral acceleration sensor 15 has an inclination of θbank_act with respect to the horizontal plane. . For this reason, the lateral acceleration sensor 15 is sensitive not only to the actual vehicle center-of-gravity lateral acceleration Accy_act but also to the acceleration component (= g * sin (θbank_act)) of the gravitational acceleration in a direction parallel to the lateral direction of the vehicle body 1B. . Therefore, the vehicle center-of-gravity lateral acceleration detected value Accy_sens as the acceleration indicated by the output of the lateral acceleration sensor 15 is actually the actual vehicle center-of-gravity lateral acceleration Accy_act in the direction parallel to the lateral direction of the vehicle body 1B of the gravitational acceleration. This is a detected value of acceleration (= Accy_act + g * sin (θbank_act)) formed by superimposing acceleration components (including the case where θbank_act = 0).

  In the following description, the sum (= Accx−g * sin) of the vehicle center-of-gravity longitudinal acceleration Accx and the acceleration component (= −g * sin (θslope)) of the gravitational acceleration in the direction parallel to the longitudinal direction of the vehicle body 1B. The acceleration defined as (θslope)) (that is, the acceleration to which the longitudinal acceleration sensor 14 is sensitive) is referred to as sensor-sensitive longitudinal acceleration Accx_sensor. Similarly, it is defined as the sum (= Accx + g * sin (θbank)) of the vehicle center-of-gravity lateral acceleration Accy and the acceleration component of the gravitational acceleration in the direction parallel to the lateral direction of the vehicle body 1B (= g * sin (θbank)). The acceleration (that is, the acceleration to which the lateral acceleration sensor 15 is sensitive) is referred to as a sensor-sensitive lateral acceleration Accy_sensor, where the sensor-sensitive longitudinal acceleration Accx_sensor matches the vehicle center-of-gravity longitudinal acceleration Accx when θslope = 0. The acceleration Accy_sensor coincides with the vehicle center-of-gravity lateral acceleration Accy when θbank = 0. Therefore, the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens generated by the longitudinal acceleration detection means 22e and the vehicle generated by the lateral acceleration detection means 22f. The center-of-gravity lateral acceleration detection value Accy_sens strictly means the detection values of the sensor-sensitive longitudinal acceleration Accx_sensor and the sensor-sensitive lateral acceleration Accy_sensor, respectively.

  The wheel torque detection value Tq_i_sens (i = 1, 2, 3, 4) is calculated by the wheel torque detection means 22g from the output of the brake pressure sensor 9-i and the output of the accelerator sensor 12 and the transmission sensor 11 respectively. Generated. Specifically, the wheel torque detection means 22g recognizes the output torque (requested torque) of the engine 3 from the detected value of the depression amount of the accelerator pedal indicated by the output value of the accelerator sensor 12, and outputs the transmission sensor 4a. The reduction ratio between the engine 3 and each wheel 2-i is recognized from the detected value of the transmission ratio of the transmission 4a indicated by the value. The wheel torque detection means 22g is configured to drive torque transmitted from the engine 3 to each wheel 2-i based on the recognized output torque of the engine 3 and the reduction ratio (each wheel 2 by the drive system of the vehicle 1). -Drive torque applied to -i). Further, based on the brake pressure detection value indicated by the output value of the brake pressure sensor 9-i, the braking torque applied to each wheel 2-i from each braking mechanism 7-i (each wheel 2-by the braking system of the vehicle 1). braking torque applied to i). Then, for each wheel 2-i, the value of the sum of the obtained drive torque and braking torque (synthetic torque) is calculated as a wheel torque detection value Tq_i_sens.

  The above is the details of the processing of S100 (processing of the observation target amount detection means 22).

  In the processing of the observation target amount detection unit 22, the sensor output may be input to the detection units 22a to 22g after passing through a filter such as a high cut filter for removing high frequency noise components. . Alternatively, the detection value of the observation target amount obtained by using the output of the sensor as it is is used as a provisional detection value, and the provisional detection value is passed through a filter such as a high cut filter, so that A detection value may be generated.

  In particular, for the vehicle center-of-gravity lateral acceleration detection value Accy, means for detecting or estimating the roll angle of the vehicle body 1B (relative inclination angle around the roll axis of the vehicle body 1B with respect to the road surface) (for example, detecting the stroke of the suspension with a sensor, In the case of providing a means for calculating the roll angle of the vehicle body 1B from the detected value), the influence of the output of the lateral acceleration sensor 15 accompanying the roll motion of the vehicle body 1B (the lateral acceleration sensor 15 is inclined by the roll angle of the vehicle body 1B). Accordingly, the influence of gravity acceleration included in the output of the acceleration sensor 15 is estimated using the observed value of the roll angle, and the estimated influence is subtracted from the acceleration detection value indicated by the output value of the lateral acceleration sensor 15. Thus, it is desirable to obtain the vehicle center-of-gravity lateral acceleration detection value Accy.

  After executing the processing of the observation target amount detection unit 22 as described above, the control device 20 executes the processing of S102 to S116 by the vehicle model calculation unit 24.

  Hereinafter, this process will be described in detail with reference to FIGS.

  As shown in FIG. 5, the vehicle model calculation means 24 has, as its function, a wheel contact load estimation unit 24 a for obtaining a contact load estimated value Fz_i_estm of each wheel 2-i and a wheel coordinate system upper wheel of each wheel 2-i. A wheel friction force estimator 24b for obtaining a driving / braking force estimated value Fsubx_i_estm which is an estimated value of the x-axis direction component of the two-dimensional road reaction force ↑ Fsub_i and a lateral force estimated value Fsuby_i_estm which is an estimated value of the y-axis direction component; A resultant force calculation unit 24c for obtaining a road surface reaction force combined translational force vector ↑ Fg_total_estm and a total road reaction force combined yaw moment Mgz_total_estm, a vehicle motion estimation unit 24d for determining a vehicle motion state quantity estimated value (including a model estimated value), and each wheel 2-i wheel traveling speed vector estimated value ↑ Vi_estm wheel traveling speed vector estimating unit 24e, wheel motion estimating unit 24f determining wheel speed estimated value Vw_i_estm of each wheel 2-i, and each wheel 2-i The wheel side slip angle estimating unit 24g for obtaining the estimated wheel side slip angle βi_estm and the wheel slip rate estimating unit 24h for obtaining the wheel slip rate estimated value κi_estm of each wheel 2-i are provided.

  In the processing of S102 to S116, first, in S102, the ground contact load estimation value Fz_i_estm of each wheel 2-i is calculated by the wheel ground load estimation unit 24a.

  In this case, in this embodiment, the wheel contact load estimating unit 24a uses the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens and the vehicle center-of-gravity lateral acceleration detection value Accy_sens among the detection values of the observation target amount obtained in S100. The ground load estimated value Fz_i_estm (i = 1, 2, 3, 4) is calculated by the following equation 1-1.

Fz_i_estm = Fz0_i + Wx_i * Accx_sens + Wy_i * Accy_sens ...... Formula 1-1

Here, Fz0_i in Formula 1-1 is the value of the ground load Fz_i of the i-th wheel 2-i when the vehicle 1 is stopped (still) on a horizontal road surface (hereinafter referred to as a ground load reference value). , Wx_i is a weighting factor that defines the change in the ground load Fz_i (change from Fz0_i) of the i-th wheel 2-i depending on the vehicle center-of-gravity longitudinal acceleration Accx, and Wy_i is the i-th wheel depending on the vehicle center-of-gravity lateral acceleration Accy. 2-i is a weighting factor that defines a change in the ground load Fz_i (change from Fz0_i). These values of Fz0_i, Wx_i, and Wy_i are predetermined values set in advance.

  Therefore, Formula 1-1 is the amount of change from the ground load reference value Fz0_i (the amount of change from the ground load reference value Fz0_i) due to the acceleration of the center of gravity of the vehicle 1 (acceleration in the direction orthogonal to the yaw axis direction). ) Is obtained by a linear combination of the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens and the vehicle center-of-gravity lateral acceleration detection value Accy_sens, and a value obtained by adding the change to the ground load reference value Fz0_i is calculated as a ground load estimated value Fz_i_estm. is there.

  The relationship between the vehicle center-of-gravity longitudinal acceleration Accx and the vehicle center-of-gravity lateral acceleration Accy and the ground load Fz_i is mapped, and the vehicle center-of-gravity longitudinal acceleration detected value Accx_sens and the vehicle center-of-gravity lateral acceleration detected value Accy_sens are mapped to the map. Based on this, the ground load estimated value Fz_i_estm of each wheel 2-i may be obtained.

  Further, Fz_i_estm may be obtained by reflecting the dynamic characteristics of the suspension device (not shown) of the vehicle 1. For example, the dynamic characteristics of the suspension device of the vehicle 1 are modeled in association with the rotational motion (roll motion) around the roll axis of the vehicle body 1B and the rotational motion (pitch motion) around the pitch axis. Then, a motion state quantity related to roll motion or pitch motion, for example, an observed value of the tilt angle of the vehicle body 1B around the roll axis and its change rate, an observed value of the tilt angle of the vehicle body 1B around the pitch axis and its change rate, Using the model showing the dynamic characteristics of the suspension device, the translational force in the vertical direction (yaw axis direction) acting on each wheel 2-i from the suspension device is estimated. Then, for each wheel 2-i, the estimated translational force and the gravity acting on the wheel 2-i are added together to obtain a ground load estimated value Fz_i_estm of each wheel 2-i. In this way, the accuracy of the ground load estimated value Fz_i_estm (i = 1, 2, 3, 4) can be further increased.

  Further, when the change in the ground load Fz_i of each wheel 2-i can be considered to be sufficiently small, the processing of S102 is omitted, and the ground load estimated value Fz_i_estm is set to a predetermined value (for example, the ground load standard). The value Fz0_i) may be set.

  As described above, when the ground load estimated value Fz_i_estm (i = 1, 2, 3, 4) is determined without using the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens and the vehicle center-of-gravity lateral acceleration detection value Accy_sens, It is not necessary to input Accx_sens and Accy_sens to the wheel ground load estimation unit 24a.

  Next, in S104, the wheel traveling speed vector estimation unit 24e calculates the wheel traveling speed vector estimated value ↑ Vi_estm of each wheel 2-i.

In this case, the wheel traveling speed vector estimation unit 24e is a vehicle in the vehicle motion state quantity estimated value (previous value) calculated by the process of S114 (process by the vehicle motion estimation unit 24d) described later in the previous calculation processing cycle. From the center-of-gravity longitudinal speed estimated value Vgx_estm_p, the vehicle center-of-gravity skid speed model estimated value Vgy_predict_p, the yaw rate estimated value γ_estm_p, and each wheel position vector ↑ Pi (= (Px_i, Py_i) ^T ), 2, each wheel traveling speed vector estimated value ↑ Vi_estm (= (Vx_i_estm, Vy_i_estm) ^T ) is calculated.

↑ Vi_estm = (Vx_i_estm, Vy_i_estm) ^T
= (Vgx_estm_p, Vgy_predict_p) ^T
+ (− Py_i * γestm_p, Px_i * γestm_p) ^T ...... Equation 1-2

Here, the second term on the right side of Expression 1-2 is the i-th wheel with respect to the center of gravity of the vehicle 1 caused by the rotational motion around the yaw axis of the vehicle 1 (rotational motion where the yaw rate value is γestm_p). 2-i relative speed (relative speed in a direction perpendicular to the yaw axis direction).

  Note that the yaw rate detection value γ_sens (previous value or current value) may be used instead of the estimated yaw rate value (previous value) γ_estm_p in Expression 1-2. Also, a wheel speed selection detection value Vw_i_sens_select (previous value or current value), which will be described later, may be used instead of the estimated vehicle center-of-gravity longitudinal speed estimated value (previous value) Vgx_estm_p in Expression 1-2.

  Next, in S106, the wheel slip ratio estimation unit 24h calculates the wheel slip ratio estimated value κi_estm of each wheel 2-i.

  In this case, the wheel slip ratio estimation unit 24h detects the front wheel steering angle detection value (current value) δf_sens (= δ1_sens = δ2_sens) among the detection values of the observation target amount obtained in S100, and the later calculation processing cycle. The wheel speed estimated value (previous value) Vw_i_estm_p (i = 1, 2, 3, 4) calculated in the process of S116 (the calculation process by the wheel motion estimation unit 24f) and the wheel traveling speed vector estimation calculated in S114 Each wheel slip ratio estimated value κi_estm is calculated from the value (current value) ↑ Vi_estm (i = 1, 2, 3, 4).

  Specifically, the wheel slip ratio estimation unit 24h first converts the wheel traveling speed vector estimated value ↑ Vi_estm into the wheel coordinate system by the following equation 1-3 for each wheel 2-i, thereby Calculate the wheel traveling speed vector estimated value ↑ Vsub_i_estm on the coordinate system.

↑ Vsub_i_estm = Rot (−δi_sens) * ↑ Vi_estm …… Formula 1-3

In this case, in Expression 1-3, the front wheel steering angle detection value δf_sens is used as the values of δ1_sens and δ2_sens for the front wheels 2-1 and 2-2. In the present embodiment, since the rear wheels 2-3 and 2-4 are non-steering wheels, the values of δ3_sens and δ4_sens in Expression 1-3 are set to “0”. Accordingly, for the rear wheels 2-3 and 2-4, since ↑ Vsub_3_estm = ↑ V3_estm and ↑ Vsub_4_estm = ↑ V4_estm, the calculation process of Expression 1-3 may be omitted.

  In addition, when the wheel traveling speed vector estimated value ↑ Vsub_i_estm of each wheel coordinate system is not used in the y-axis direction component estimated value Vsuby_i_estm in the calculation processing (processing of S108, etc.) described later, the wheel traveling speed vector on each wheel coordinate system. Only the x-axis direction component estimated value Vsubx_i_estm of the estimated value ↑ Vsub_i_estm may be calculated.

  For each wheel 2-i, the wheel slip ratio estimation unit 24h calculates the wheel coordinate system wheel traveling speed vector estimated value ↑ Vsub_i_estm x-axis direction component estimated value Vsubx_i_estm calculated as described above, and the wheel speed estimated value ( The wheel slip ratio estimated value κi_estm is calculated from the previous value) Vw_i_estm_p according to the following expression 1-4.

κi_estm = (Vsubx_i_estm−Vw_i_estm_p) / max (Vsubx_i_estm, Vw_i_estm_p)
... Formula 1-4

In this case, when the vehicle 1 that applies driving force to the front wheels 2-1 and 2-2, which are drive wheels, from the drive system of the vehicle 1 is accelerated, Vsubx_i_estm ≦ Vw_i_estm_p, and therefore κi_estm ≦ 0. Further, when the vehicle 1 decelerates the braking force applied from the braking system of the vehicle 1 to each wheel 2-i, Vsubx_i_estm ≧ Vw_i_estm_p, and therefore κi_estm ≧ 0.

  Note that the wheel speed detection value Vw_i_sens (previous value or current value) may be used instead of the estimated wheel speed value (previous value) Vw_i_estm_p in Formula 1-4. In such a case, the wheel motion estimation unit 24f, which will be described in detail later, is unnecessary.

  Next, in S108, the wheel side slip angle estimating unit 24g calculates the wheel side slip angle estimated value βi_estm of each wheel 2-i.

  In this case, the wheel skid angle estimation unit 24g detects the front wheel steering angle detection value δf_sens (= δ1_sens = δ2_sens) among the detection values of the observation target amount obtained in S100, and the wheel traveling speed vector estimation value calculated in S104. ↑ Each wheel side slip angle estimated value βi_estm is calculated from Vi_estm (i = 1, 2, 3, 4).

  Specifically, the wheel side slip angle estimation unit 24g first calculates, for each wheel 2-i, from the X-axis direction component estimated value Vx_i_estm and the Y-axis direction component estimated value Vy_i_estm of the wheel speed progress velocity vector estimated value ↑ Vi_estm. A wheel position side slip angle estimated value β0i_estm is calculated by Formula 1-5.

β0i_estm = tan ⁻¹ (Vy_i_estm / Vx_i_estm) ...... Formula 1-5

Then, for each wheel 2-i, the wheel side slip angle estimating unit 24g estimates the wheel side slip angle from the wheel position side slip angle estimated value β0i_estm calculated as described above and the rudder angle detected value δi_sens by the following equation 1-6. The value βi_estm is calculated.

βi_estm = β0i_estm−δi_sens ...... Formula 1-6

In this case, in Expression 1-6, the front wheel steering angle detection value δf_sens is used as the values of δ1_sens and δ2_sens for the front wheels 2-1 and 2-2. In the present embodiment, since the rear wheels 2-3 and 2-4 are non-steering wheels, the values of δ3_sens and δ4_sens in Expression 1-6 are set to “0”. Therefore, β3_estm = β03_estm and β4_estm = β04_estm.

  It should be noted that the wheel side slip angle is calculated by the following equation 1-7 from the estimated value Vsubx_i_estm of the wheel traveling speed vector estimated value ↑ Vsub_i_estm on the wheel coordinate system calculated by the equation 1-3 and the y-axis direction component estimated value Vsuby_i_estm. The estimated value βi_estm may be calculated.

βi_estm = tan ⁻¹ (Vsuby_i_estm / Vsubx_i_estm) ...... Formula 1-7

Next, in S110, the wheel frictional force estimating unit 24b calculates an upper wheel two-dimensional road surface reaction force estimated value ↑ Fsub_i (= (Fsubx_i_estm, Fsuby_i_estm) ^T ) of each wheel 2-i.

  Here, the wheel frictional force estimation unit 24b includes a friction characteristic model that expresses a relationship between slippage between the wheels 2-i and the road surface reaction force acting on the wheels 2-i from the road surface. In the present embodiment, the friction characteristic model includes a driving / braking force Fsubx_i and a lateral force Fsuby_i in the wheel coordinate system upper wheel two-dimensional road surface reaction force ↑ Fsub_i as a friction force acting on each wheel 2-i from the road surface. As shown in the following formulas 1-8 and 1-9, the wheel slip ratio κi and the wheel slip angle βi indicating the slip state of the i-th wheel 2-i, the ground load Fz_i, and the road surface friction coefficient μ are input. It is a model expressed as a function as a parameter.

Fsubx_i = func_fxi (κi, βi, Fz_i, μ) ...... Formula 1-8
Fsuby_i = func_fyi (κi, βi, Fz_i, μ) ...... Equation 1-9

In this case, the function func_fxi (κi, βi, Fz_i, μ) on the right side of Expression 1-8, that is, the function func_fx_i that defines the relationship between Fsubx_i and κi, βi, Fz_i, and μ is In the example, it is represented by the following formula 1-8a.

func_fx_i (κi, βi, Fz_i, μ) = μ * Cslp_i (κi) * Cattx_i (βi) * Fz_i
... Formula 1-8a

In this expression 1-8a, Cslp_i (κi) is a coefficient that defines the change characteristic of the driving / braking force Fsubx_i accompanying the change in the wheel slip ratio κi, and Cattx_i (βi) is the change in the wheel skid angle βi (and hence the lateral force). This is a coefficient that defines the change characteristic of the driving / braking force Fsubx_i accompanying the change in Fsuby_i. The relationship between Cslp_i (κi) and κi is set, for example, as shown in the graph of FIG. That is, the relationship is set so that the coefficient Cslp_i (κi) becomes a monotone decreasing function with respect to the wheel slip rate κi. More specifically, in the situation where κi> 0 (the situation when the vehicle 1 is decelerated), the value of the function func_fx_i (= driving / braking force Fsubx_i) becomes negative ( In the situation where the braking force increases (in the direction of increasing braking force) and κi <0 (the situation during acceleration of the vehicle 1), the value of the function func_fx_i (= drive · The relationship between Cslp_i (κi) and κi is set so that the braking force Fsubx_i changes in the positive direction (increase in driving force). In the relationship shown in FIG. 6A, the coefficient Cslp_i (κi) has a saturation characteristic with respect to the wheel slip rate κi. That is, as the absolute value of κi increases, the ratio of the change in Cslp_i (κi) to the change in κi (the value obtained by differentiating Cslp_i (κi) by κi) decreases.

  Further, the relationship between the coefficient Cattx_i (βi) and the wheel side slip angle βi is set as shown in the graph of FIG. 6B, for example. That is, this relationship is set so that the value of the coefficient Cattx_i (βi) approaches “0” from “1” as the absolute value of the wheel slip angle βi increases from “0”. In other words, the relationship between Cattx_i (βi) and βi is reduced so that the value of the function func_fx_i (= drive / braking force Fsubx_i) decreases as the absolute value of the wheel slip angle βi increases. Is set. This corresponds to the fact that the magnitude of the lateral force Fsuby_i generally increases and the magnitude of the driving / braking force Fsubx_i decreases as the absolute value of the wheel side slip angle βi increases.

  Therefore, the friction characteristic model represented by the expressions 1-8 and 1-8a is that the driving / braking force Fsubx_i of the i-th wheel 2-i is proportional to the road surface friction coefficient μ and the ground load Fz_i, and the wheel slip In this model, Fsubx_i becomes a monotonically decreasing function with respect to the rate κi, and the magnitude of Fsubx_i decreases as the absolute value of the wheel slip angle βi increases.

  The function func_fyi (κi, βi, Fz_i, μ) on the right side of Expression 1-9, that is, the function func_fyi that defines the relationship between Fsuby_i and κi, βi, Fz_i, and μ is an example of this embodiment. Then, it is represented by the following formula 1-9a.

func_fy_i (κi, βi, Fz_i, μ) = μ * Cbeta_i (βi) * Catty_i (κi) * Fz_i
... Formula 1-9a

In this equation 1-9a, Cbeta_i (βi) is a coefficient that defines the change characteristic of the lateral force Fsuby_i accompanying the change in the wheel side slip angle βi, and Catty_i (κi) is the change in the wheel slip ratio κi (and hence the driving / braking force). This is a coefficient that defines the change characteristic of the lateral force Fsuby_i accompanying the change of Fsubx_i. The relationship between Cbeta_i (βi) and βi is set as shown in the graph of FIG. 7A, for example. That is, the relationship is set so that the coefficient Cbeta_i (βi) is a monotonically decreasing function with respect to the wheel side slip angle βi. More specifically, in a situation where βi> 0 (a situation where Vsuby_i> 0), the value of the function func_fy_i (= lateral force Fsuby_i) becomes negative (i-th wheel) as the wheel slip angle βi increases. 2-i to the right) and when βi <0 (situation where Vsuby_i <0), the value of the function func_fy_i (= lateral force Fsuby_i) increases as the wheel slip angle βi increases. ) Increases in the positive direction (to the left of the i-th wheel 2-i), the relationship between Cbeta_i (βi) and βi is set. In the relationship shown in FIG. 7A, the coefficient Cbeta_i (βi) has a saturation characteristic with respect to the wheel side slip angle βi. That is, as the absolute value of βi increases, the ratio of the change in coefficient Cbeta_i (βi) to the change in βi (the value obtained by differentiating Cbeta_i (βi) with βi) decreases.

  Further, the relationship between the coefficient Catty_i (κi) and the wheel slip rate κi is set as shown in the graph of FIG. 7B, for example. That is, the relationship is set so that the value of the coefficient Catty_i (κi) approaches “0” from “1” as the absolute value of the wheel slip ratio κi increases from “0”. In other words, the relationship between Cattyx_i (κi) and κi is set so that the magnitude of the lateral force Fsuby_i as the value of the function func_fy_i decreases as the absolute value of the wheel slip ratio κi increases. Yes. This corresponds to the fact that the magnitude of the driving / braking force Fsubx_i generally increases and the magnitude of the lateral force Fsuby_i decreases as the absolute value of the wheel slip ratio κi increases.

  Therefore, the friction characteristic model represented by the expressions 1-9 and 1-9a is such that the lateral force Fsuby_i of the i-th wheel 2-i is proportional to the road surface friction coefficient μ and the ground load Fz_i, and the wheel skid angle βi In contrast, Fsuby_i is a monotonically decreasing function, and the Fsuby_i becomes smaller as the absolute value of the wheel slip ratio κi becomes larger.

  In S110, the wheel frictional force estimator 24b obtains the wheel coordinate system upper wheel two-dimensional road surface reaction force estimated value ↑ Fsub_i of each wheel 2-i using the friction characteristic model set as described above. Specifically, for each wheel 2-i, the wheel frictional force estimating unit 24b calculates the wheel slip rate estimated value κi_estm calculated in S106, the wheel side slip angle estimated value βi_estm calculated in S108, and calculated in S102. The ground contact load estimated value Fz_i_estm and the road surface friction coefficient estimated value μ_estm_p calculated in the process of S122 (calculated by the μ estimator 26) described later in the previous calculation processing cycle are respectively represented by the function func_fxi (κi, βi). , Fz_i, μ) and func_fyi (κi, βi, Fz_i, μ) are used as input parameter values to perform the calculation of the right side of the expression 1-8a and the calculation of the right side of the expression 1-9a. Then, the wheel frictional force estimating unit 24b drives the value of the function func_fxi obtained by the calculation of Expression 1-8a as the x-axis direction component estimated value of the wheel two-dimensional road surface reaction force estimated value ↑ Fsub_i. -Estimated braking force Fsubx_i_estm. Further, the wheel frictional force estimation unit 24b uses the value of the function func_fyi obtained by the calculation of Expression 1-9a as the y-axis direction component estimated value of the wheel coordinate system upper wheel two-dimensional road surface reaction force estimated value ↑ Fsub_i. The force estimated value is Fsuby_i_estm. In this case, the value of the coefficient Cslp_i (κi) necessary for the calculation of the right side of the expression 1-8a is determined based on the map representing the relationship shown in FIG. 6A from the wheel slip rate estimated value κi_estm. Further, the value of the coefficient Catty_i (βi) necessary for the calculation of the right side of the expression 1-8a is determined from the estimated wheel side slip angle βi_estm based on the map representing the relationship shown in FIG. Further, the value of Cbeta_i (βi) necessary for the calculation of the right side of the expression 1-9a is determined based on the wheel lateral slip ratio estimated value βi_estm based on the map representing the relationship shown in FIG. Further, the value of the coefficient Cattx_i (κi) necessary for the calculation of the right side of Expression 1-9a is determined from the wheel slip ratio estimated value κi_estm based on the map representing the relationship shown in FIG.

  As described above, of the road surface reaction force acting on each wheel 2-i, the estimated driving / braking force value Fsubx_i_estm and the lateral force estimation as the estimated value of the road surface reaction force (friction force) having dependency on the road surface friction coefficient μ. The value Fsuby_i_estm is calculated using the latest value (previous value μ_estm_p) of the road surface friction coefficient estimated value μ_estm and the friction characteristic model.

  Supplementally, in the present embodiment, the function func_fx_i is set so that the driving / braking force Fsubx_i of each wheel 2-i is proportional to the road surface friction coefficient μ. For example, the function func_fx_i is set by the following expression 1-8b. May be.

func_fx_i (κi, βi, Fz_i, μ) = Cslp2_i (μ, κi) * Cattx_i (βi) * Fz_i
... Formula 1-8b

Cslp2_i (μ, κi) in the expression 1-8b is a coefficient that defines the change characteristics of the driving / braking force Fsubx_i accompanying changes in the road surface friction coefficient μ and the wheel slip ratio κi, and μ * in the expression 1-8a. It is a more generalized version of Cslp_i (κi). In this case, the relationship between the coefficient Cslp2_i (μ, κi), the road surface friction coefficient μ, and the wheel slip ratio κi is set as shown in the graph of FIG. This relationship is set so that the coefficient Cslp2_i (μ, κi) becomes a monotonically decreasing function with respect to the wheel slip ratio κi, and at the same time the absolute value thereof becomes a monotonically increasing function with respect to the road surface friction coefficient μ. FIG. 8 representatively illustrates a graph of Cslp2_i (μ, κi) corresponding to three types of road surface friction coefficient μ. In the relationship shown in FIG. 8, the coefficient Cslp2_i (μ, κi) has a saturation characteristic with respect to the wheel slip ratio κi. That is, when the absolute value of κi increases, the magnitude of the rate of change of the coefficient Cslp_i (μ, κi) with respect to the increase of κi (the value obtained by partial differentiation of Cslp_i (μ, κi) with κi) becomes the absolute value of κi. It becomes small with the increase of.

  When the function func_fx_i is set as described above, a non-linear relationship can be set between the driving / braking force Fsubx_i of each wheel 2-i and the road surface friction coefficient μ.

  As for the function func_fy_i related to the lateral force Fsuby_i of each wheel 2-i, as in the case of the function func_fx_i related to the driving force Fsubx_i, instead of μ * Cbeta_i (βi) in Expression 1-9a, the road surface friction coefficient μ Also, a coefficient Cbeta2_i (μ, βi) that defines the change characteristic of the lateral force Fsuby_i accompanying the change of the wheel side slip angle βi may be used.

  The function func_fy_i related to the lateral force Fsuby_i of each wheel 2-i may be configured with the driving / braking force Fsubx_i as an input parameter instead of the wheel slip rate κi. In this case, as the value of Fsubx_i, the driving / braking force estimated value Fsubx_i_estm obtained as described above by the function func_fx_i of the expression 1-8a or the expression 1-8b may be used. The braking force detection value Fsubx_i_sens may be used. That is, in S100, based on the wheel torque detection value Tq_i_sens of each wheel 2-i generated by the observation target amount detection means 22 and the wheel speed detection value Vw_i_sens, the driving / braking force is detected by the following expression 1-8c. The value Fsubx_i_sens is obtained.

Fsubx_i_sens = Tq_i_sens / Rw_i−Vwdot_i_sens * Iw_i / Rw_i ² Equation 1-8c

Vwdot_i_sens on the right side of Expression 1-8c is a temporal change rate (differential value) of the wheel speed detection value Vw_i_sens. In addition, as the values of the wheel effective radius Rw_i and the wheel inertia moment Iw_i in Expression 1-8c, predetermined values set in advance are used. The second term on the right side of Equation 1-8c may be replaced with the term ωwdot_i_sens * Iw_i / Rw_i that uses ωwdot_i_sens, which is a differential value of the wheel rotational angular velocity detection value ωw_i_sens indicated by the output value of the wheel rotational angular velocity sensor 8-i. Good.

  Returning to the description of FIG. 4, next, in S112, the resultant force calculation unit 24c calculates the total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm and the total road surface reaction force combined yaw moment estimated value Mgz_total_estm.

  In this case, the resultant force calculation unit 24c calculates the ground load estimated value Fz_i_estm of each wheel 2-i calculated in S102, and the driving / braking force estimated value Fsubx_i_estm and lateral force estimated value of each wheel 2-i calculated in S110. From Fsuby_i_estm and the front wheel rudder angle detection value δf_sens (= δ1_sens = δ2_sens) among the detection values of the observation target amount obtained in S100, the total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm and the total road surface reaction force combination The yaw moment estimated value Mgz_total_estm is calculated.

Specifically, the resultant force calculation unit 24c first calculates, for each wheel 2-i, a two-dimensional road surface reaction force vector estimated value ↑ Fsub_i_estm (= (Fsubx_i_estm, Fsuby_i_estm) ^T ) on the wheel coordinate system according to the following formula 1- 10 to calculate the two-dimensional road surface reaction force vector estimated value ↑ Fi_estm = (Fx_i_estm, Fy_i_estm) ^T.

↑ Fi_estm = Rot (δi_sens) * ↑ Fsub_i_estm ...... Formula 1-10

In this case, in Formula 1-10, the front wheel steering angle detection value δf_sens is used as the values of δ1_sens and δ2_sens for the front wheels 2-1 and 2-2. In the present embodiment, since the rear wheels 2-3 and 2-4 are non-steering wheels, the values of δ3_sens and δ4_sens in Expression 1-10 are set to “0”. Therefore, for rear wheels 2-3 and 2-4, since ↑ F3_estm = ↑ Fsub_3_estm and ↑ F4_estm = ↑ Fsub_4_estm, the arithmetic processing of Expression 1-10 may be omitted.

Next, the resultant force calculation unit 24c calculates the total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm (= (Fgx_total_estm, Fgy_total_estm, Fgz_total_estm) ^T ) by the following expression 1-11, and also calculates the total road surface by the following expression 1-12. Reaction force synthetic yaw moment estimated value Mgz_total_estm is calculated.

↑ Fg_total_estm = (ΣFx_i_estm, ΣFy_i_estm, ΣFz_i_estm) ^T ...... Equation 1-11
Mgz_total_estm = Σ (↑ Pi × ↑ Fi_estm) ...... Formula 1-12

Note that “Σ” in Equations 1-11 and 1-12 means the sum of all the wheels 2-i (i = 1, 2, 3, 4). Further, ↑ Pi × ↑ Fi_estm in the right side of Expression 1-12 is the outer product of the wheel position vector ↑ Pi of the i-th wheel 2-i and the two-dimensional road surface reaction force vector estimated value ↑ Fi_estm. By the two-dimensional road surface reaction force vector estimated value ↑ Fi_estm of the wheel 2-i, it means a moment around the yaw axis generated at the center of gravity of the vehicle 1.

  Supplementally, calculation of the yaw axis direction component Fgz_total_estm in ↑ Fg_total_estm may be omitted.

  Next, in S114, the vehicle motion estimation unit 24d uses the vehicle motion state quantity estimated value (including the model estimated value) as the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm, the vehicle center-of-gravity skid speed estimated value Vgy_estm, and the vehicle center-of-gravity skid speed model estimation. A value Vgy_predict, a yaw rate estimated value γ_estm, and the like are calculated.

  Here, the vehicle motion estimation unit 24 d includes a vehicle motion model that represents the relationship between the resultant force of the road surface reaction force as an external force acting on the vehicle 1 and the motion of the vehicle 1. In this embodiment, the vehicle motion model is represented by the following expressions 1-13 to 1-15.

Fgx_total = m * (Vgdot_x−Vgy * γ) ...... Formula 1-13
Fgy_total = m * (Vgdot_y + Vgx * γ) ...... Formula 1-14
Mgz_total = Iz * γdot ...... Formula 1-15

Equations 1-13 and 1-14 represent dynamic equations relating to the translational motion of the center of gravity of the vehicle 1 in the X-axis direction and the Y-axis direction of the vehicle body coordinate system, respectively. Equation 1-15 represents a dynamic equation relating to the rotational motion of the vehicle 1 around the yaw axis. Note that the vehicle motion model in the present embodiment is a model on the assumption that the road surface on which the vehicle 1 is traveling is a horizontal plane (the road surface bank angle θbank and the road surface slope angle θslope are both “0”).

  In S114, the vehicle motion estimator 24d, the vehicle motion model represented by the above formulas 1-13 to 1-15, the total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm and the total road surface reaction force calculated in S112. A vehicle motion state estimated value is calculated using the synthesized yaw moment estimated value Mgz_total_estm. In this case, for some vehicle motion state quantity estimated values, the previous values of the some vehicle motion state quantity estimated values are also used to calculate them. Further, for some vehicle motion state quantity estimated values, the part of vehicle motion state quantity estimated values are calculated so as to approach the detected values obtained in S100 (so as not to deviate from the detected values). .

  Specifically, the vehicle motion estimator 24d uses the following equations 1-13a to 1-15a obtained from the equations 1-13 to 1-15, respectively, to estimate the vehicle center-of-gravity longitudinal velocity change rate Vgdot_x_estm and the vehicle center of gravity. Side slip velocity change rate estimated value Vgdot_y_estm and yaw angular acceleration estimated value γdot_estm are calculated.

Vgdot_x_estm = Fgx_total_estm / m + Vgy_predict_p * γ_estm_p ...... Equation 1-13a
Vgdot_y_estm = Fgy_total_estm / m−Vgx_estm_p * γ_estm_p ...... Equation 1-14a
γdot_estm = Mgz_total_estm / Iz Equation 1-15a

In this case, Fx_total_estm, Fy_total_estm, and Mgz_total_estm in Equations 1-13a to 1-15a are the values calculated in S112 (current value), and Vgy_predict_p, Vgx_estm_p, and γ_estm_p are determined in S114 in the previous calculation processing cycle, respectively. Value (previous value). Further, predetermined values set in advance are used as the value of the vehicle mass m in the expressions 1-13a and 1-14a and the value of the vehicle yaw inertia moment Iz in the expression 1-15a.

  Supplementally, the yaw rate detection value γ_sens (previous value or current value) may be used instead of the estimated yaw rate value (previous value) γ_estm_p in Equations 1-13a and 1-14a. Further, a wheel speed selection detection value Vw_i_sens_select (previous value or current value), which will be described later, may be used instead of the vehicle center longitudinal speed estimated value (previous value) Vgx_estm_p in Expression 1-14a.

  Next, the vehicle motion estimator 24d calculates the vehicle center-of-gravity longitudinal velocity change rate estimated value Vgdot_x_estm, the vehicle center-of-gravity skid velocity change rate estimated value Vgdot_y_estm, the yaw angular acceleration estimated value γdot_estm, and the vehicle center-of-gravity longitudinal velocity estimated value obtained as described above. From the previous value Vgx_estm_p of the vehicle, the previous value Vgy_predict_p of the vehicle center-of-gravity skid speed model estimated value, and the previous value γ_estm_p of the estimated yaw rate value, respectively, according to the following equations 1-18, 1-19, 1-20 Vehicle center-of-gravity longitudinal velocity model estimated value Vgx_predict as the vehicle center-of-gravity longitudinal speed model value, vehicle center-of-gravity side-slip velocity model estimated value Vgy_predict as the value of vehicle center-of-gravity side-slip velocity on the vehicle motion model, and vehicle motion model A yaw rate model estimated value γ_predict as a yaw rate value is calculated.

Vgx_predict = Vgx_estm_p + Vgdot_x_estm * ΔT (Formula 1-18)
Vgy_predict = Vgy_predict_p + Vgdot_y_estm * ΔT ...... Equation 1-19
γ_predict = γ_estm_p + γdot_estm * ΔT Equation 1-20

In addition, ΔT in Expressions 1-18 to 1-20 is an arithmetic processing cycle of the control device 20. The right sides of these equations 1-18 to 1-20 correspond to the integral operation of Vgdot_x_estm, the integral operation of Vgdot_y_estm, and the integral operation of γdot_estm, respectively.

  Here, in the present embodiment, the vehicle motion estimation unit 24d causes the yaw rate estimated value γ_estm (and thus the yaw rate model estimated value γ_predict) to approach the yaw rate detected value γ_sens with respect to the yaw rate γ among the motion state quantities to be estimated. (Do not deviate from γ_sens). The vehicle motion estimator 24d also detects the vehicle center of gravity longitudinal speed estimated value Vgx_estm (and thus the vehicle center of gravity longitudinal speed model estimated value Vgx_predict) for the vehicle center of gravity longitudinal speed Vgx having the meaning as the vehicle speed of the vehicle 1 to detect the wheel speed. It is determined so as to approach the vehicle center of gravity longitudinal speed recognized from the value Vw_i_sens (i = 1, 2, 3, 4) (so as not to deviate from the recognized vehicle center of gravity longitudinal speed).

  Therefore, the vehicle motion estimator 24d calculates the yaw rate deviation γestm_err as the deviation between the yaw rate detected value γ_sens obtained in S100 and the yaw rate model estimated value γ_predict calculated by the equation 1-20 as described above with respect to the yaw rate γ. Calculated according to 1-21. Further, the vehicle motion estimation unit 24d detects and detects the wheel speed that is one of the wheel speed detection values Vw_i_sens (i = 1, 2, 3, 4) obtained in S100 with respect to the vehicle center-of-gravity longitudinal speed Vgx. A vehicle speed deviation Vgx_estm_err as a deviation between the value Vw_i_sens_select and the vehicle longitudinal speed model estimated value Vgx_predict calculated by the expression 1-18 as described above is calculated by the following expression 1-22. The wheel speed selection detection value Vw_i_sens_select corresponds to the detection value of the actual vehicle speed based on the wheel speed detection value Vw_i_sens (i = 1, 2, 3, 4) (the detection value of the actual vehicle center-of-gravity longitudinal speed Vgx_act). This is a value selected from the speed detection value Vw_i_sens (i = 1, 2, 3, 4). In this case, when the vehicle 1 is accelerated, the slowest wheel speed detection value among the wheel speed detection values Vw_i_sens (i = 1, 2, 3, 4) is selected as the wheel speed selection detection value Vw_i_sens_select. Further, when the vehicle 1 is decelerated, the fastest wheel speed detection value among the wheel speed detection values Vw_i_sens (i = 1, 2, 3, 4) is selected as the wheel speed selection detection value Vw_i_sens_select.

γestm_err = γ_sens−γ_predict ...... Equation 1-21
Vgx_estm_err = Vw_i_sens_select−Vgx_predict (Formula 1-22)

Next, the vehicle motion estimation unit 24d determines the final vehicle center-of-gravity longitudinal velocity estimated value Vgx_estm and the yaw rate estimated value γ_estm in the current computation processing cycle by the following equations 1-23 and 1-24, respectively.

Vgx_estm = Vgx_predict + Kvx * Vgx_estm_err ...... Equation 1-23
γ_estm = γ_predict + Kγ * γestm_err (Formula 1-24)

Note that Kvx in Equation 1-23 and Kγ in Equation 1-24 are gain coefficients of a predetermined value (≦ 1) set in advance, respectively.

  As shown in these expressions 1-23 and 1-24, in this embodiment, the vehicle center-of-gravity longitudinal speed model estimated value Vgx_predict (estimated value on the vehicle motion model) calculated by the expression 1-18 is In accordance with the vehicle speed deviation Vgx_estm_err calculated by the equation 1-22, the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm is corrected by a feedback control law (here, a proportional law) so that the vehicle speed deviation Vgx_estm_err approaches 0. Is determined. Further, the yaw rate model estimated value γ_predict (estimated value on the vehicle motion model) calculated by the expression 1-20 is set to the yaw rate deviation γ_estm_err according to the yaw rate deviation γ_estm_err calculated by the expression 1-21. The yaw rate estimated value γ_estm is determined by correcting the feedback control law (here, the proportional law) so as to approach 0 ″. As described above, in this embodiment, the vehicle center longitudinal velocity estimated value Vgx_estm as the vehicle speed of the vehicle 1 on the vehicle motion model is not deviated from the wheel speed selection detection value Vw_i_sens_select as the actual vehicle speed detection value (Vw_i_sens_select and To match or nearly match). Further, the yaw rate estimated value γ_estm as the yaw rate of the vehicle 1 on the vehicle motion model is determined so as not to deviate from the yaw rate detected value γ_sens as the detected value of the actual yaw rate γ_act (so as to coincide with or substantially coincide with γ_sens). . Further, in the present embodiment, the vehicle center-of-gravity longitudinal speed model estimated value Vgx_predict, which is calculated by the above equations 1-18 and 1-20, using the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm and the yaw rate estimated value γ_estm determined in this way, Since the yaw rate model estimated value γ_predict is calculated, as a result, Vgx_predict and γ_predict are also determined so as not to deviate from Vw_i_sens_select and γ_sens, respectively. Therefore, in the present embodiment, Vgx_estm, Vgx_predict, γ_estm, and γpredict are determined so that the relationship of Vgx_estm≈Vgx_predict≈Vw_i_sens_select and γ_estm≈γpredict≈γ_sens is maintained.

  On the other hand, in the present embodiment, the vehicle motion estimator 24d performs processing shown in the flowchart of FIG. 9 to obtain a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by Equation 1-19. The vehicle center-of-gravity skid speed estimation value Vgy_estm is determined. In the vehicle model calculation means 24, in the calculation process for calculating the state quantity of the vehicle 1 using the value of the vehicle center-of-gravity skid speed Vgy (the calculation process of the expressions 1-2, 1-13a, and 1-19), Vgy_estm is Not used, Vgy_predict is used. That is, the vehicle model calculation means 24 executes the calculation process on the assumption that the value of the vehicle center-of-gravity skid speed Vgy on the vehicle motion model always matches the vehicle center-of-gravity skid speed model estimated value Vgy_predict.

  In the process shown in the flowchart of FIG. 9, the vehicle motion estimation unit 24d first determines the vehicle center of gravity as an acceleration value obtained by dividing the total road surface reaction force combined lateral force estimated value Fgy_total_estm by the vehicle mass m in S114-1. The lateral acceleration estimated value Accy_estm is obtained by the calculation of the first term on the right side of the expression 1-14a. That is, the vehicle motion estimation unit 24d calculates Accy_estm by dividing the road surface reaction force combined lateral force estimated value Fgy_total_estm (current value) calculated in S112 by the vehicle mass m, as in the following expression 1-41a.

Accy_estm = Fgy_total_estm / m ...... Formula 1-41a

From the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm (current value) calculated by the above equation 1-14a, the previous value Vgx_estm_p of the vehicle center-of-gravity longitudinal speed estimated value, and the previous value γ_estm_p of the yaw rate estimated value, The vehicle center-of-gravity lateral acceleration estimated value Accy_estm may be calculated by -41b.

Accy_estm = Vgdot_y_estm + Vgx_estm_p * γ_estm_p ...... Equation 1-41b

In this case, the yaw rate detection value γ_sens (previous value or current value) may be used instead of the estimated yaw rate value (previous value) γ_estm_p in Equation 1-41b. Also, the wheel speed as a detected value of the actual vehicle speed based on the wheel speed detection value Vw_i_sens (i = 1, 2, 3, 4) instead of the vehicle center-of-gravity longitudinal speed estimated value (previous value) Vgx_estm_p in Formula 1-41b. The selection detection value Vw_i_sens_select (previous value or current value) may be used.

  Next, in S114-2, the vehicle motion estimation unit 24d determines the vehicle center-of-gravity lateral acceleration which is a deviation between the vehicle center-of-gravity lateral acceleration detected value Accy_sens obtained in S100 and the vehicle center-of-gravity lateral acceleration estimated value Accy_estm calculated as described above. The acceleration deviation Accy_err is calculated by the following equation 1-42.

Accy_err = Accy_sens−Accy_estm ...... Formula 1-42

Supplementally, when the vehicle 1 is traveling on a horizontal road surface, Accy_sens has a meaning as a detected value of the actual vehicle center-of-gravity lateral acceleration Accy_act (= Vgdot_y_act + Vgx_act * γ_act). Therefore, when the vehicle 1 is traveling on a horizontal road surface, the second term on the right side of the formula 1-41b, that is, the lateral direction of the center of gravity of the vehicle 1 caused by the centrifugal force accompanying the turning motion of the vehicle 1 In the state where the estimated value of the acceleration component of the vehicle coincides with or substantially coincides with the actual value of the acceleration component (= Vgx_act * γ_act), the vehicle center-of-gravity lateral acceleration deviation Accy_err is the actual vehicle center-of-gravity skid velocity change rate Vgdot_y_act The deviation (= Vgdot_y_act−Vgdot_y_estm) from the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm (estimated value on the vehicle motion model) calculated by the equation 1-14a. In other words, the vehicle center-of-gravity lateral acceleration deviation Accy_err corresponds to an error (= Vgdot_y_act−Vgdot_y_estm) of the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm with respect to the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act.

  Further, in S114-3, the vehicle motion estimation unit 24d estimates the yaw angular acceleration as the value of the yaw angular acceleration γdot generated in the vehicle 1 on the vehicle model by the external force moment of the total road surface reaction force combined yaw moment estimated value Mgz_total_estm. The value γdot_estm is calculated by the above equation 1-15a. That is, γdot_estm is calculated by dividing Mgz_total_estm by the vehicle yaw moment of inertia Iz. In each calculation processing cycle, in order to obtain the yaw rate provisional estimated value γ_predict by the equation 1-20, if γdot_estm has already been calculated by 1-15a, it is necessary to calculate γdot_estm again in S114-3. There is no.

  Next, in S114-4, the vehicle motion estimator 24d subtracts the yaw angular acceleration estimated value γdot_estm calculated by the equation 1-15a from the yaw angular acceleration detected value γdot_sens obtained in S100, thereby obtaining the yaw angular acceleration. The deviation γdot_err is calculated. That is, γdot_err is calculated by the following equation 1-43.

γdot_err = γdot_sens−γdot_estm ...... Formula 1-43

Next, in S114-5, the vehicle motion estimator 24d calculates the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by Equation 1-19 as described above, the vehicle center-of-gravity lateral acceleration deviation Accy_err and the yaw angular acceleration deviation γdot_err. The value corrected in accordance with is determined as the vehicle center-of-gravity skid speed estimated value Vgy_estm (current value).

  The process of S114-5 is executed by, for example, the process shown in the block diagram of FIG.

  First, the outline of this process will be described below. First, the vehicle motion estimator 24d uses a frequency component adjustment filter 24d10 that has a low-cut characteristic (a characteristic that cuts off a low-frequency component equal to or lower than a predetermined frequency) for the vehicle center-of-gravity lateral acceleration deviation Accy_err and yaw angular acceleration deviation γdot_err, Pass 24d11. As a result, when the vehicle center of gravity lateral acceleration deviation Accy_err includes a steady offset component due to the drift of the output of the lateral acceleration sensor 15 or the like, the vehicle center of gravity lateral direction is formed by removing the offset component. The acceleration deviation filtering value Accy_err_lowcut is output from the filter 24d10. Similarly, when a steady offset component is included in the yaw angular acceleration deviation γdot_err due to the drift of the output of the yaw rate sensor 13, the yaw angular acceleration deviation filtering is performed by removing the offset component. The value γdot_err_lowcut is output from the filter 24d11. In other words, Accy_err_lowcut and γdot_err_lowcut are a high frequency component of the vehicle center of gravity lateral acceleration deviation Accy_err and a high frequency component of the yaw angular acceleration deviation γdot_err, respectively.

  In this embodiment, the filters 24d10 and 24d11 are both first-order low-cut filters whose transfer functions are expressed by T3 * S / (1 + T3 * S), and their time constants T3 are the same. Is set to a value.

  Next, the vehicle motion estimator 24d calculates the basic correction operation amount for correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict according to the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angular acceleration deviation filtering value γdot_err_lowcut. The value Vgdot_y_cmpn is obtained by processing within the frame line in FIG. 10 (details will be described later). The basic value Vgdot_y_cmpn has the meaning as an error of the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm as the temporal change rate (differential value) of the vehicle center-of-gravity skid speed model estimated value Vgy_predict with respect to the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act. It is what you have. Hereinafter, the basic value Vgdot_y_cmpn is referred to as a side slip speed change rate necessary correction amount Vgdot_y_cmpn.

  Further, the vehicle motion estimator 24d converts the side slip velocity change rate necessary correction amount Vgdot_y_cmpn into a frequency component adjustment filter 24d22 having high cut characteristics and a gain multiplier 24d23 that multiplies an input value by a gain T4 having a predetermined value. As a result, a corrected manipulated variable Vgy_cmpn (hereinafter referred to as a skid speed corrected manipulated variable Vgy_cmpn) used for actual correction of the vehicle center-of-gravity skid speed model estimated value Vgy_predict is obtained.

  In this case, the filter 24d22 having a high cut characteristic is a high cut filter (first-order low-pass filter having a time constant T4) whose transfer function is expressed by 1 / (1 + T4 * S). The gain T4 multiplied by the output of the filter 24d22 by the gain multiplier 24d23 is set so as to coincide with the time constant T4 of the filter 24d22. The time constant T4 of the transfer function of the high cut filter 24d22 is such that the cutoff frequency of the high cut filter 24d22 defined by the time constant T4 is greater than the cutoff frequency defined by the time constant T3 of the transfer functions of the low cut filters 24d10 and 24d11. Is set to be higher.

  Then, the vehicle motion estimation unit 24d determines a value obtained by adding the side slip speed correction manipulated variable Vgy_cmpn to the vehicle center of gravity side slip speed model estimated value Vgy_predict in the addition calculation unit 24d24 as the vehicle center of gravity side slip speed estimated value Vgy_estm. . That is, the vehicle motion estimator 24d corrects the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by the expression 1-19 by the following expression 1-44 using the skid speed correction manipulated variable Vgy_cmpn. It is determined as the estimated center-of-gravity skid speed Vgy_estm.

Vgy_estm = Vgy_predict + Vgy_cmpn ...... Equation 1-44

The above is the outline of the process of S114-5.

  Here, the principle of the process of determining the skid speed correction manipulated variable Vgy_cmpn will be described before describing the processing in the broken line frame in FIG. 10 in detail.

  First, the side slip velocity change rate required correction amount Vgdot_y_cmpn determined by the processing within the broken line frame in FIG. 10 is described later. The change in the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut indicates the actual side slip motion of the vehicle 1. When there is a high possibility that it has occurred due to a change, it is determined to match Accy_err_lowcut. In such a case, the skid speed correction manipulated variable Vgy_cmpn is determined by passing Accy_err_lowcut through the filter 24d22 having high cut characteristics and the gain multiplier 24d23.

  In this case, in principle, the process of passing the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut (or Accy_err) through the filter 24d22 having high cut characteristics and the gain multiplication unit 24d23 is the transfer function T4. * S / (1 + T4 * S) This is equivalent to a process of passing through a low cut filter (first-order low cut filter of time constant T4) and an integrator whose transfer function is represented by 1 / S.

  Also, since Accy_err is equivalent to the error (= Vgdot_y_act−Vgdot_y_estm) of the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm with respect to the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act as described above, the result of integrating Accy_err is The vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm is an integral value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict with respect to the actual vehicle center-of-gravity skid speed Vgy_act (= Vgy_act−Vgy_predict). .

  For this reason, a value obtained by passing Accy_err_lowcut (or Accy_err) through a low cut filter (first-order low cut filter of time constant T4) and an integrator, and thus Accy_err_lowcut (or Accy_err), is used as the high cut filter 24d22 and the gain multiplication unit 24d23. It is considered that the value obtained by passing through is basically converged to an error (= Vgy_act−Vgy_predict) of the vehicle center-of-gravity skid speed model estimated value Vgy_predict with respect to the actual vehicle center-of-gravity skid speed Vgy_act or a value close thereto. Therefore, basically, a value obtained by passing Accy_err_lowcut (or Accy_err) through the high cut filter 24d22 and the gain multiplier 24d23 to the vehicle center-of-gravity skid speed model estimated value Vgy_predict is greater than Vgy_predict. It is considered that the actual vehicle gravity center skid speed Vgy_act approaches.

  However, the vehicle center-of-gravity lateral acceleration detection value Accy_sens (= sensor-sensitive lateral acceleration detection value Accy_sensor_sens) based on the output of the lateral acceleration sensor 15 is caused not only by the change in the skid motion state quantity of the vehicle 1 but also by the actual road surface bank angle θbank_act. Therefore, the vehicle center-of-gravity lateral acceleration deviation Accy_err also changes according to the actual road surface bank angle θbank_act. Therefore, particularly in the transition period in which the actual road surface bank angle θbank_act changes, even if the actual vehicle center-of-gravity skid speed Vgy_act is constant, the side slip speed correction manipulated variable Vgy_cmpn changes and is eventually determined. The vehicle center-of-gravity skid speed estimated value Vgy_estm is likely to vary with respect to Vgy_act.

  Therefore, in the present embodiment, the vehicle motion estimation unit 24d determines the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angle in order to suppress the variation in the vehicle center-of-gravity skid speed estimated value Vgy_estm due to the change in the actual road bank angle θbank_act. The acceleration slip filtering value γdot_err_lowcut is used to determine the necessary correction amount Vgdot_y_cmpn for the skid speed change rate obtained by removing the influence of the change in the actual road bank angle θbank_act from the Accy_err_lowcut by the processing in the broken line frame of FIG. Then, the side slip speed correction manipulated variable Vgy_cmpn is determined from the side slip speed change rate necessary correction amount Vgdot_y_estm through the high cut filter 24d22 and the gain multiplier 24d23.

  In this case, the process in the broken line frame in FIG. 10 (process for determining Vgdot_y_estm) is a process constructed based on the phenomenon described below.

  For example, when the vehicle 1 is making a steady turn in a clockwise direction (direction of γ_act <0) on a horizontal road surface having a constant actual road surface friction coefficient μ_act, the actual road surface bank angle θbank_act is “ Assume that the value has changed from 0 "to a positive value. In this case, immediately after the change of the actual road surface bank angle θbank_act, the absolute value of Accy_sens (<0) decreases due to the influence of the lateral component of the vehicle 1 in the gravitational acceleration. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the positive side. On the other hand, when the vehicle 1 turns in the clockwise direction on the road surface where θbank_act> 0, in the vehicle 1 where the NSP exists behind the center of gravity of the vehicle 1 (vehicle 1 where Lnsp> 0), Since the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to increase, the yaw angular acceleration deviation γdot_err changes to the negative side. In addition, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 in which Lnsp <0), the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to decrease. Therefore, γdot_err changes to the positive side. Therefore, when attention is paid to a value α2 * γdot_err obtained by multiplying γdot_err by an appropriate coefficient having the same polarity as the vehicle center-of-gravity / NSP distance Lnsp (hereinafter referred to as Lnsp homopolarity coefficient α2), this α2 * γdot_err is It changes to the negative side which is a different polarity from Accy_err.

  Further, for example, when the vehicle 1 is making a steady turning in a clockwise direction (direction of γ_act <0) on a horizontal road surface having a constant actual road surface friction coefficient μ_act, the actual road surface bank angle θbank_act Is assumed to change from “0” to a negative value. In this case, immediately after the change of the actual road surface bank angle θbank_act, the absolute value of Accy_sens (<0) increases due to the influence of the lateral component of the vehicle 1 in the gravitational acceleration. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the negative side. On the other hand, during turning in the clockwise direction of the vehicle 1 on the road surface where θbank_act <0, in the vehicle 1 where the NSP is present behind the center of gravity of the vehicle 1 (vehicle 1 where Lnsp> 0), Since the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to decrease, the yaw angular acceleration deviation γdot_err changes to the positive side. Further, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 in which Lnsp <0), the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to increase. Therefore, γdot_err changes to the negative side. For this reason, the α22 * γdot_err changes to the positive side, which is a polarity side different from Accy_err.

  Further, for example, when the vehicle 1 is making a steady turn in a counterclockwise direction (direction of γ_act> 0) on a horizontal road surface having a constant actual road surface friction coefficient μ_act, the actual road surface bank angle Assume that θbank_act changes from “0” to a positive value. In this case, immediately after the change of the actual road surface bank angle θbank_act, the absolute value of Accy_sens (> 0) increases due to the influence of the lateral component of the vehicle 1 in the gravitational acceleration. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the positive side. On the other hand, when the vehicle 1 turns in the counterclockwise direction on the road surface where θbank_act> 0, the vehicle 1 where the NSP exists behind the center of gravity of the vehicle 1 (the vehicle 1 where Lnsp> 0) Since the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to decrease, the yaw angular acceleration deviation γdot_err changes to the negative side. In addition, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 in which Lnsp <0), the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to increase. Therefore, γdot_err changes to the positive side. For this reason, the α22 * γdot_err changes to a negative side which is a polarity side different from Accy_err.

  Further, for example, when the vehicle 1 is making a steady turn in a counterclockwise direction (direction of γ_act> 0) on a horizontal road surface having a constant actual road surface friction coefficient μ_act, the actual road surface bank angle Assume that θbank_act changes from “0” to a negative value. In this case, immediately after the actual road surface bank angle θbank_act changes, the absolute value of Accy_sens (> 0) decreases due to the influence of the lateral component of the vehicle 1 in the gravitational acceleration. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the negative side. On the other hand, when the vehicle 1 turns in the counterclockwise direction on the road surface where θbank_act <0, the NSP is located behind the center of gravity of the vehicle 1 (the vehicle 1 where Lnsp> 0), Since the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to increase, the yaw angular acceleration deviation γdot_err changes to the positive side. Further, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 where Lnsp <0), the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to decrease. Therefore, γdot_err changes to the negative side. For this reason, the α2 * γdot_err changes to the positive side which is a different polarity from Accy_err.

  As described above, the product α2 * γdot_err of the yaw angular acceleration deviation γdot_err and the Lnsp homopolarity coefficient α2 is basically the vehicle center-of-gravity lateral acceleration deviation Accy_err in the transition period immediately after the actual road surface bank angle θbank_act changes. It changes to a different polarity side (reverse polarity side). As a result, a value α2 * γdot_errr_lowcut (a high frequency component of α2 * γdot_err) obtained by multiplying the yaw angular acceleration deviation filtering value γdot_err_lowcut by the Lnsp homopolarity coefficient α2 is obtained when the actual road bank angle θbank_act changes. It will change to the polarity side (opposite polarity side) different from the acceleration deviation filtering value Accy_err_lowcut.

  On the other hand, when the vehicle 1 is making a steady turn in a clockwise direction (direction of γ_act <0) on a horizontal road surface, for example, the vehicle 1 is caused by a decreasing change in the actual road surface friction coefficient μ_act. Assume that the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act changes to the positive side due to skidding. In this case, immediately after the actual road surface friction coefficient μ_act changes, the absolute value of Accy_sens (<0) decreases. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the positive side. On the other hand, when a side slip of the vehicle 1 occurs due to a decrease in the actual road surface friction coefficient μ_act, the vehicle 1 in which the NSP is located behind the center of gravity of the vehicle 1 (the vehicle 1 with Lnsp> 0) Then, since the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to decrease, the yaw angular acceleration deviation γdot_err changes to the positive side. Further, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 in which Lnsp <0), the absolute value of the actual yaw rate γ_act (<0) of the vehicle 1 tends to increase. Therefore, γdot_err changes to the negative side. Therefore, the α2 * γdot_err changes to the positive side that is the same polarity side as Accy_err.

  Further, for example, when the vehicle 1 is making a steady turn in a counterclockwise direction (direction of γ_act> 0) on a horizontal road surface, for example, due to a decreasing change in the actual road surface friction coefficient μ_act. Assuming that the vehicle 1 skids, the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act changes to the negative side. In this case, the absolute value of Accy_sens (> 0) decreases immediately after the change in the actual road surface friction coefficient μ_act. As a result, the vehicle center-of-gravity lateral acceleration deviation Accy_err changes to the negative side. On the other hand, when a side slip of the vehicle 1 occurs due to a decrease in the actual road surface friction coefficient μ_act, the vehicle 1 in which the NSP is located behind the center of gravity of the vehicle 1 (the vehicle 1 with Lnsp> 0) Then, since the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to decrease, the yaw angular acceleration deviation γdot_err changes to the negative side. In addition, in the vehicle 1 in which the NSP exists ahead of the center of gravity of the vehicle 1 (the vehicle 1 in which Lnsp <0), the absolute value of the actual yaw rate γ_act (> 0) of the vehicle 1 tends to increase. Therefore, γdot_err changes to the positive side. Therefore, the α2 * γdot_err changes to the negative side that is the same polarity side as Accy_err.

  As described above, the product α2 * γdot_err of the yaw angular acceleration deviation γdot_err and the Lnsp same sign coefficient α2 is basically when the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act changes to either the positive side or the negative side. Even in the transition period immediately after the change, the vehicle gravity center lateral acceleration deviation Accy_err changes to the same polarity side. As a result, the value α2 * γdot_errr_lowcut (high frequency component of α2 * γdot_err) obtained by multiplying the yaw angular acceleration deviation filtering value γdot_err_lowcut by the Lnsp same sign coefficient α2 indicates whether the actual vehicle center-of-gravity skid velocity change rate Vgdot_y_act is positive or negative. Even if it changes to, it changes to the same polarity side as the vehicle gravity center lateral acceleration deviation filtering value Accy_err_lowcut.

  Since Accy_err_lowcut and γdot_err_lowcut are obtained by passing Accy_err and γdot_err through filters 24d6 and 24d7 having low cut characteristics, respectively, the above-described characteristics regarding the polarities of Accy_err_lowcut and γdot_err_lowcut are the outputs of the lateral acceleration sensor 15 and the yaw rate sensor 13. Therefore, it is difficult to be affected by the steady offset of Accy_err and γdot_err due to drift of the. For this reason, the change in polarity of Accy_err_lowcut and γdot_err_lowcut is symmetrical between the positive polarity side and the negative polarity side.

  From the above, when the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut changes to the positive side or the negative side, the product α2 * γdot_err_lowcut of the yaw angular acceleration deviation filtering value γdot_err_lowcut and the Lnsp homopolarity coefficient α2 is the same as Accy_err_lowcut. In a situation where the polarity changes, it is highly likely that the change in Accy_err_lowcut has occurred due to a change in the actual skidding motion of the vehicle 1 (translational motion in the lateral direction of the vehicle 1). On the other hand, in a situation where the product α2 * γdot_err_lowcut changes to the opposite polarity side to Accy_err_lowcut, it is highly likely that the change in Accy_err_lowcut is caused by the change in the actual road bank angle θbank_act.

  Further, for example, the sum of Accy_err_lowcut and the above product α2 * γdot_err_lowcut, that is, the weight coefficients applied to Accy_err_lowcut and γdot_err_lowcut are set to “1” and “α2”, respectively, and the linear combination value obtained by linearly combining these Accy_err_lowcut and γdot_err_lowcut ( = Accy_err_lowcut + α2 * γdot_err_lowcut (hereinafter, this is referred to as a linear combination value SUM).

  In this case, the situation in which the linear combination value SUM has a polarity different from Accy_err_lowcut (= 1 * Accy_err_lowcut) as the first term included therein is that Accy_err_lowcut and α2 * γdot_err_lowcut as the second term of SUM are mutually In this situation, the polarities are different and the absolute value of α2 * γdot_err_lowcut (second term of SUM) is larger than the absolute value of Accy_err_lowcut (first term of SUM). For this reason, this situation is considered to be a situation where the influence of the change in the bank angle of the road surface is strongly generated.

  The situation where the linear combination value SUM has the same polarity as Accy_err_lowcut (SUM first term) is that Accy_err_lowcut (SUM first term) and α2 * γdot_err_lowcut (SUM second term) have the same polarity. And Accy_err_lowcut (SUM first term) and α2 * γdot_err_lowcut (SUM second term) have different polarities, and Accy_err_lowcut (SUM first term) has an absolute value of α2 * γdot_err_lowcut ( One of the situations in which the absolute value is larger than the absolute value of the second term of SUM). For this reason, this situation is considered to be a situation in which the bank angle of the road surface is constant or the influence of the change is weak, and the influence of the change in the friction coefficient of the road surface and the motion state of the vehicle is strongly generated. .

  As a value of the Lnsp same sign coefficient α2 as a weighting coefficient applied to γdot_err_lowcut, for example, a value obtained by dividing the vehicle yaw moment of inertia Iz by the product of the vehicle mass m and the vehicle center of gravity / NSP distance Lnsp (= When set to Iz / (m * Lnsp)), the weight coefficients applied to Accy_err and γdot_err are set to “1” and “α2”, respectively, and a linear combination value (= Accy_err + α2) obtained by linearly combining these Accy_err and γdot_err * Γdot_err) corresponds to a value obtained by dividing an NSP yaw moment error Mnsp_err, which will be described later, by (m * Lnsp), and is proportional to the Mnsp_err. Therefore, the linear combination value SUM is proportional to a value obtained by passing the NSP yaw moment error Mnsp_err through a low-cut characteristic filter (a high-frequency component of Mnsp_err). Due to the characteristics of Mnsp_err described later, the linear combination value SUM is maintained at “0” or a value close to this even when the actual road bank angle θbank_act changes in a state where the error of the road surface friction coefficient estimated value μ_estm is small. .

  In the processing in the broken line frame of FIG. 10 in the present embodiment, based on what has been described above, the side slip speed correction manipulated variable is calculated from the vehicle center of gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angular acceleration deviation filtering value γdot_err_lowcut as follows. The required slip amount change rate Vgdot_y_cmpn as a basic value of Vgy_cmpn is determined.

  That is, the vehicle motion estimation unit 24d inputs the yaw angular acceleration deviation filtering value γdot_err_lowcut to the coefficient multiplication unit 24d12, and the coefficient multiplication unit 24d12 calculates a product α2 * γdot_err_lowcut obtained by multiplying γdot_err_lowcut by the Lnsp homopolarity coefficient α2. . In this case, in the present embodiment, α2 is set to a predetermined value Iz / (m * Lnsp). Note that predetermined values set in advance are used as the value of the vehicle yaw inertia moment Iz, the value of the vehicle mass m, and the value of the vehicle center-of-gravity / NSP distance Lnsp necessary for setting the value of α2.

  Then, the vehicle motion estimation unit 24d inputs the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut to the processing units 24d13 and 24d14, and inputs the product α2 * γdot_err_lowcut to the processing units 24d15 and 24d16. The processing units 24d13 and 24d16 both output the input value as it is when the input value ≧ 0, and output “0” regardless of the input value when the input value <0. The process which performs is performed. In other words, the processing units 24d13 and 24d16 output max (input value, 0). The processing units 24d14 and 24d15 both output the input value as it is when the input value ≦ 0, and “0” regardless of the input value when the input value> 0. Is executed. In other words, the processing units 24d14 and 24d15 output min (input value, 0).

  Further, the vehicle motion estimation unit 24d adds the output (≧ 0) of the processing unit 24d13 and the output (≦ 0) of the processing unit 24d15 in the addition operation unit 24d17. Further, the vehicle motion estimation unit 24d adds the output of the processing unit 24d14 (≦ 0) and the output of the processing unit 24d16 (≧ 0) in the addition calculation unit 24d18.

  Next, the vehicle motion estimation unit 24d inputs the outputs of the addition calculation units 24d17 and 24d18 to the processing units 24d19 and 24d20, respectively, and adds the outputs of these processing units 24d19 and 24d20 in the addition calculation unit 25d21, thereby causing the skidding. The speed change rate required correction amount Vgdot_y_cmpn is calculated. In this case, the processing unit 24d19 has the same function as the processing units 24d13 and 24d16, and outputs max (input value, 0). The processing unit 24d20 has the same function as the processing units 24d14 and 24d15, and outputs min (input value, 0).

  The above is the details of the processing in the broken line frame of FIG. 10 in the present embodiment.

  According to the process of the block diagram of FIG. 10 described above (the process of S114-5 of FIG. 9), when Accy_err_lowcut and α2 * γdot_err_lowcut (α2 = Iz / (m * Lnsp)) have the same polarity, that is, When it is considered that there is a high possibility that the change in Accy_err_lowcut is caused by the change in the actual side-slip motion of the vehicle 1, the output of one of the processing units 24d15 and 24d16 coincides with Accy_err_lowcut, Output becomes “0”. Therefore, in this case, the side slip velocity change rate necessary correction amount Vgdot_y_cmpn, which is the output of the addition operation unit 25d21, matches Accy_err_lowcut. Therefore, the skid speed correction manipulated variable Vgy_cmpn in this case is determined as a value obtained by passing Accy_err_lowcut through the high cut filter 24d22 and the gain multiplier 24d23 as it is.

  On the other hand, if Accy_err_lowcut and α2 * γdot_err_lowcut (α2 = Iz / (m * Lnsp)) have different polarities, that is, the change in Accy_err_lowcut may have occurred due to the change in the actual road bank angle θbank_act. When it is considered that the output is high, whether one of the processing units 24d19 and 24d20 is “0” and the other output is the linear combination value SUM (when SUM has the same polarity as Accy_err_lowcut) Or “0” (when SUM has opposite polarity to Accy_err_lowcut). Accordingly, in this case, the side slip velocity change rate necessary correction amount Vgdot_y_cmpn, which is the output of the addition operation unit 25d21, has the same polarity as Accy_err_lowcut and is closer to “0” than Accy_err_lowcut, or “0”. become. Therefore, as a result, the skid speed correction manipulated variable Vgy_cmpn in this case is determined to be a value closer to “0” than the value obtained by passing Accy_err_lowcut through the high cut filter 24d22 and the gain multiplier 24d23, or “ 0 "will be determined.

  In other words, when the linear combination value SUM has a polarity different from that of Accy_err_lowcut (the first term of SUM) by the process of FIG. 10 (the process of S114-5 of FIG. 9) in the present embodiment, α2 * γdot_err_lowcut (second term of SUM) has a polarity different from that of Accy_err_lowcut (first term of SUM), and the absolute value of α2 * γdot_err_lowcut (second term of SUM) is equal to that of Accy_err_lowcut (first term of SUM) When it is larger than the absolute value, the skid speed correction manipulated variable Vgy_cmpn is always set to “0”. If the linear combination value SUM has the same polarity as Accy_err_lowcut (SUM first term), that is, α2 * γdot_err_lowcut (SUM second term) has the same polarity as Accy_err_lowcut (SUM first term). Or when the absolute value of α2 * γdot_err_lowcut (second term of SUM) is smaller than the absolute value of Accy_err_lowcut (first term of SUM), the value closer to “0” of SUM and Accy_err_lowcut Is set as the side slip speed correction manipulated variable Vgy_cmpn. More specifically, when α2 * γdot_err_lowcut has the same polarity as Accy_err_lowcut (in this case, | SUM |> | Accy_err_lowcut |), Accy_err_lowcut is set as Vgy_cmpn, and α2 * γdot_err_lowcut has a polarity different from that of Accy_err_lowcut. In some cases (in this case, | SUM | <| Accy_err_lowcut |), SUM is set as Vgy_cmpn.

  A value obtained by adding the side slip speed correction manipulated variable Vgy_cmpn determined as described above to the vehicle center-of-gravity side slip speed model estimated value Vgy_predict is determined as the vehicle center-of-gravity side slip speed estimated value Vgy_estm.

  The above is the detail of the process of S114 (process of the vehicle motion estimation part 24d).

  Here, a supplementary description will be given of the correspondence between the present embodiment and the present invention. In the present embodiment, the position of the center of gravity of the vehicle 1 corresponds to a predetermined position of the vehicle in the present invention.

Further, in the present embodiment, the vehicle model calculation in the present invention is performed by the processing of the vehicle model calculation means 24 (the processing of S102 to S116 in FIG. 4 except for the processing of FIG. 9 executed in the processing of S114). Means are realized. In this case, in the present embodiment, the vehicle model according to the present invention is realized by the arithmetic expression executed by the vehicle model arithmetic means 24 (the arithmetic processing of the expressions 1-1 to 1-24). Further, the friction characteristic model represented by the expressions 1-8 and 1-8a and the friction characteristic model represented by the expressions 1-9 and 1-9a correspond to the friction characteristic model in the present invention. Further, the wheel coordinate system upper wheel two-dimensional road surface reaction force estimated value ↑ Fsub_i (= (Fsubx_i_estm, Fsuby_i_estm) ^T ) of each wheel 2-i calculated by the processing of S110 (processing of the wheel frictional force estimation unit 24b) is This corresponds to the road surface reaction force model value in the invention. Furthermore, the total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm calculated by the process of S112 (process of the resultant force calculation unit 24c) corresponds to the resultant force of the road surface reaction force model value in the present invention. Further, the detected values (δ1_sens, δ2_sens, Vw_i_sens, γ_sens, Accx_sens, Accy_sens, Tq_i_sens) input to the vehicle model calculation means 24 correspond to the observed values of the predetermined types of observation target amounts in the present invention. The detected values (δ1_sens, δ2_sens, Vw_i_sens, γ_sens, Accx_sens, Accy_sens, Tq_i_sens) of the observation target amounts are input parameter values other than the road surface friction coefficient μ (κi, βi, Fz_i) is a detection value of the observation target amount necessary for specifying. Further, the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by Equation 1-19 in the process of S114 (process of the vehicle motion estimation unit 24d) corresponds to the skid motion state quantity model value in the present invention. In this case, in order to calculate the current value as a new value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict, the previous value Vgy_predict_p as the past calculated value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict is used.

  Further, the lateral acceleration sensor 14 and the lateral acceleration detection means 22f of the observation target amount detection means 22 realize the predetermined position actual lateral acceleration detection means in the present invention. In this case, the actual sensor-sensitive lateral acceleration Accy_sensor_act corresponds to the predetermined position actual lateral acceleration in the present invention, and the vehicle center-of-gravity lateral acceleration detected value (sensor-sensitive lateral acceleration detected value) Accy_sens corresponds to the predetermined position actual lateral acceleration detected value in the present invention. Equivalent to.

  Further, the yaw rate acceleration detecting means in the present invention is realized by the yaw rate sensor 13 and the yaw angular acceleration detecting means 22d of the observation target amount detecting means 22. In this case, the yaw axis passing through the center of gravity of the vehicle 1 corresponds to the predetermined yaw axis in the present invention, and the detected yaw angular acceleration value γdot_sens corresponds to the detected angular acceleration value in the present invention.

  Further, in the present embodiment, the lateral acceleration model according to the present invention is obtained by the processing of FIG. 9 executed in the processing of S112 (processing of the resultant force calculation unit 24c) and the processing of S114 (processing of the vehicle motion estimation unit 24d). A value calculating means, a lateral acceleration deviation calculating means, a yaw angular acceleration model value calculating means, a yaw angular acceleration deviation calculating means, and a skid motion state quantity estimated value determining means are realized. More specifically, the lateral acceleration model value calculation means is realized by the process of S112 (more specifically, the process of calculating the total road surface reaction force combined lateral force Fgy_total_estm in the process) and the process of S114-1 in FIG. The vehicle center-of-gravity lateral acceleration estimated value Accy_estm obtained by this processing corresponds to the lateral acceleration model value in the present invention. Further, the lateral acceleration deviation calculating means is realized by the processing of S114-2 in FIG. The vehicle center-of-gravity lateral acceleration deviation Accy_err obtained by this processing corresponds to the lateral acceleration deviation in the present invention. Further, the yaw angular acceleration model value calculation means is realized by the process of S112 (more specifically, the process of calculating the total road surface reaction force combined yaw moment Mgz_total_estm in the process) and the process of S114-3 of FIG. The yaw angular acceleration estimated value γdot_estm obtained by this processing corresponds to the yaw angular acceleration model value in the present invention. Further, the yaw angular acceleration deviation calculating means is realized by the processing of S114-4 in FIG. The yaw angular acceleration deviation γdot_err obtained by this processing corresponds to the yaw angular acceleration deviation in the present invention. Further, the skid motion state quantity estimated value determining means is realized by the processing of S114-5 of FIG. 9 (processing of the block diagram of FIG. 10). The vehicle center-of-gravity skid speed estimated value Vgy_estm obtained by this processing corresponds to the estimated value of the skid motion state quantity in the present invention.

  Further, in the process of S114-5 as the skid motion state quantity estimated value determining means (the process of the block diagram of FIG. 10), the filters 24d10 and 24d11 function as the second filter and the third filter in the present invention, respectively. The vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angular acceleration deviation filtering value γdot_err_lowcut correspond to the second filtering value and the third filtering value in the present invention, respectively.

  Further, the correction basic value determination means in the present invention is realized by the processing in the broken line frame of the block diagram of FIG. 10, and the correction calculation means in the present invention is realized by the processing of the filter 24d22, the gain multiplication unit 24d23, and the addition calculation unit 24d24. Is done. In this case, the side slip speed change rate required correction amount Vgdot_y_cmpn corresponds to the basic value in the present invention, and the side slip speed correction operation amount Vgy_cmpn corresponds to the correction operation amount in the present invention. The filter 24d22 functions as the first filter in the present invention, and the gain multiplication unit 24d23 functions as the gain multiplication means in the present invention.

  The linear combination value SUM (= Accy_err_lowcut + α2 * γdot_err_lowcut) corresponds to the linear combination value in the present invention. In this case, the addition calculation units 24d17 and 24d18 function as means for calculating the linear combination value SUM when Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities (reverse polarities). Furthermore, in the present embodiment, when the weighting coefficient applied to the vehicle center-of-gravity lateral acceleration deviation Accy_err in the linear combination value SUM is set to α1, α1 is set to “1”, and the weighting coefficient α2 applied to γdot_err_lowcut is set to “Iz / (m * Lnsp) ”. Therefore, these weighting factors α1 and α2 are when the vehicle center-of-gravity / NSP distance Lnsp is positive (when NSP exists behind the center of gravity of vehicle 1) and when negative (NSP is the vehicle). Are set so as to have different polarities from each other. In this embodiment, since α1 = 1, the polarity of α1 * Accy_err_lowcut and the polarity of Accy_err_lowcut are the same. Therefore, the mutual relationship between the polarity of the linear combination value SUM and the polarity of α1 * Accy_err_lowcut matches the mutual relationship between the polarity of SUM and the polarity of Accy_err_lowcut. In this embodiment, α1 = 1 and α2 = Iz / (m * Lnsp). Therefore, α1, α2 is set so that the ratio α2 / α1 of α1 and α2 matches Iz / (m * Lnsp). And are set.

  Returning to the description of FIG. 4, after the processing of the vehicle motion estimation unit 24d (the processing of S114) is executed as described above, the vehicle model calculation unit 24 next performs the wheel motion estimation unit 24f in S116. A wheel speed estimated value Vw_i_estm of each wheel 2-i is calculated.

  Here, the wheel motion estimation unit 24f represents a wheel motion model that represents the relationship between the force (wheel torque Tq_i and driving / braking force) acting on each wheel 2-i and the rotational motion of the wheel 2-i. I have. In this embodiment, this wheel motion model is a model expressed by the following expression 1-27.

Tq_i−Fsubx_i * Rw_i = Iw_i * (Vwdot_i / Rw_i) (Formula 1-27)

“Vwdot_i” in Expression 1-27 is a temporal change rate (differential value) of the wheel speed Vw_i of the i-th wheel 2-i, and is hereinafter referred to as a wheel speed change rate. Further, the left side of the expression 1-27 indicates the wheel torque Tq_i applied to the i-th wheel 2-i from one or both of the driving system and the braking system of the vehicle 1, and the driving / braking force Fsubx_i of the i-th wheel 2-i. Means the combined torque with the torque applied to the wheel 2-i.

  Then, the wheel motion estimation unit 24f first calculates the wheel speed change rate estimated value Vwdot_i_estm of each wheel 2-i by the following expression 1-27a obtained based on the expression 1-27.

Vwdot_i_estm = Rw_i * (Tq_i_sens−Fsubx_i_estm * Rw_i) / Iw_i
... Formula 1-27a

In this case, Tq_i_sens in Expression 1-27a is the detection value (current value) obtained in S100 for each wheel 2-i, and Fsubx_i_estm is the value (current value) obtained in S110 for each wheel 2-i. . A predetermined value set in advance is used as the value of the wheel effective radius Rw_i and the wheel inertia moment Iw_i of each wheel 2-i.

  Next, the wheel motion estimation unit 24f calculates the wheel speed change rate estimated value Vwdot_i_estm obtained as described above and the previous value Vw_i_estm_p of the wheel speed estimated value for each wheel 2-i by the following formula 1-28. A wheel speed provisional estimated value Vw_i_predict is calculated as a provisional value of the speed estimated value.

Vw_i_predict = Vw_i_estm_p + Vwdot_i_estm * ΔT (Formula 1-28)

Expression 1-28 corresponds to the integral calculation of Vwdot_i_estm.

  Here, in the present embodiment, the wheel motion estimation unit 24f makes the wheel speed estimation value Vw_i_estm close to the wheel speed detection value Vw_i_sens, similarly to the case where the vehicle motion estimation unit 24d calculates the yaw rate estimation value γ_estm and the like. (Do not deviate from Vw_i_sens).

  Therefore, the wheel motion estimator 24f provides, for each wheel 2-i, a deviation between the wheel speed estimated value Vw_i_sens obtained in S110 and the wheel speed provisional estimated value Vw_i_predict calculated by Expression 1-28 as described above. The wheel speed deviation Vw_i_estm_err is calculated by the following equation 1-29.

Vw_i_estm_err = Vw_i_sens−Vw_i_predict …… Equation 1-29

Next, the wheel motion estimation unit 24f determines a final wheel speed estimation value Vw_i_estm in the current calculation processing cycle by the following equation 1-30 for each wheel 2-i.

Vw_i_estm = Vw_i_predict + Kvw * Vw_i_estm_err ...... Equation 1-30

In Equation 1-30, Kvw is a predetermined predetermined gain coefficient (<1).

  Therefore, in the present embodiment, each wheel speed provisional estimated value Vw_i_predict (estimated value on the wheel motion model) calculated by the expression 1-28 is set in accordance with the wheel speed deviation Vw_i_estm_err calculated by the expression 1-29. Thus, each wheel speed estimated value Vw_i_estm is determined by correcting the wheel speed deviation Vw_i_estm_err by a feedback control law (proportional law in this case) so as to approach “0”.

  The processing of S102 to S116 described above is the details of the processing of the vehicle model calculation means 24.

  Next, the control device 20 executes the process of the μ estimating means 26 in S118.

  Before describing the details of this process, first, the estimation principle of the road surface friction coefficient μ in the present embodiment will be described.

  In this case, for convenience of explanation, it is assumed that the actual dynamics of the vehicle 1 is approximately expressed by the following equation 4-1.

  Specifically, the equation 4-1 is the power of a model vehicle that includes the actual side-sliding motion of the vehicle 1 and the rotational motion about the yaw axis, one front wheel as a steering wheel and one rear wheel as a non-steering wheel. It represents a dynamic model called a so-called two-wheel model (linear two-wheel model), which is approximated as a geometrical behavior. The cornering power CPf of the front wheels in this two-wheel model corresponds to the cornering power per wheel of the front wheels 2-1 and 2-2 of the actual vehicle 1 (four-wheel vehicle), and the cornering power CPr of the rear wheels is This corresponds to the cornering power per wheel of the rear wheels 2-3 and 2-4 of the actual vehicle 1 (four-wheel vehicle).

  Here, the cornering power CPf per wheel of the front wheels 2-1 and 2-2 on the reference road surface where the value of the actual road surface friction coefficient μ_act is “1” is CPf0, and the rear wheels 2-3, 2- on the reference road surface. The cornering power CPr of 4 per wheel is set to CPr0. Then, between each of the cornering powers CPf and CPr on the road surface having an actual road surface friction coefficient μ_act of an arbitrary value and the actual road surface friction coefficient μ_act, an approximation is given as in the following equations 4-2a and 4-2b. Proportionally holds.

CPf = CPf0 * μ_act ...... Formula 4-2a
CPr = Cpr0 * μ_act ...... Formula 4-2b

By applying the equations 4-2a and 4-2b to the equation 4-1, the equation 4-1 can be rewritten as the following equation 4-3.

  Hereinafter, on the basis of the equation 4-3 (an equation expressing the linear two-wheel model), a moment around the yaw axis generated at the NSP (neutral steer point) of the vehicle 1 (that is, the NSP yamment Mnsp) is used. A method for estimating the road friction coefficient μ will be described below.

  First, the technical significance of the actual NSP yaw moment Mnsp_act related to the estimation of the road surface friction coefficient μ and the value of the actual NSP yaw moment Mnsp_act are specified from the observed state values of the motion of the vehicle 1 related thereto (estimation) The method will be described.

  The left side of the expression in the first row of Expression 4-3 means the differential value (temporal change rate) of the actual vehicle gravity center skid speed Vgy_act, that is, the actual vehicle gravity center skid speed change rate Vgdot_y_act. −3 in the first row is rewritten to the following expression 4-4.

Vgdot_y_act + Vgx_act * γ_act + g * sin (θbank_act)
= Μ_act * a11 * Vgy_act / Vgx_act
+ Μ_act * a12s * γ_act / Vgx_act + μ_act * b1 * δf_act ...... Equation 4-4

On the other hand, as is clear from the definition of the vehicle center-of-gravity lateral acceleration Accy (Accy = Vgdot_y + Vgx * γ) and the description of the sensor-sensitive lateral acceleration Accy_sensor, the left side of Equation 4-4 represents the actual sensor-sensitive lateral acceleration Accy_sensor_act (lateral The acceleration sensor 15 coincides with the actual acceleration. Therefore, the following expression 4-5 is obtained.

Accy_sensor_act = Vgdot_y_act + Vgx_act * γ_act + g * sin (θbank_act)
... Formula 4-5

From Equation 4-5, it can be seen that the left side of Equation 4-4 matches the actual sensor-sensitive lateral acceleration Accy_sensor_act. Therefore, the following expression 4-6 is obtained from the expressions 4-4 and 4-5.

Accy_sensor_act = μ_act * a11 * Vgy_act / Vgx_act
+ Μ_act * a12s * γ_act / Vgx_act + μ_act * b1 * δf_act
...... Formula 4-6

The right side of the expression 4-6 represents the lateral direction of the vehicle body 1B in the translational force vector acting on the center of gravity of the vehicle 1 by the resultant force of the actual road surface reaction force acting on each wheel 2-i from the road surface. This corresponds to a value obtained by dividing the component (that is, the X-axis direction component Fgy_total_act of the actual total road surface reaction force composite translational force vector ↑ Fg_total_act) by the vehicle mass m. Therefore, Expression 4-6 represents the relationship that Accy_sensor_act (= Accy_act + g * sin (θbank_act)) matches Fgy_total_act / m.

  Further, the left side of the expression in the second row of Expression 4-3 means the differential value (time change rate) of the actual yaw rate γ_act, that is, the actual yaw angular acceleration γdot_act. The two-line formula is rewritten as the following formula 4-7.

γdot_act = μ_act * a21 * Vgy_act / Vgx_act
+ Μ_act * a22 * γ_act / Vgx_act + μ_act * b2 * δf_act
... Formula 4-7

The right side of the equation 4-7 represents the moment around the yaw axis acting on the center of gravity of the vehicle 1 (ie, the actual total road surface reaction) by the resultant force of the actual road reaction force acting on each wheel 2-i from the road surface. This is equivalent to a value obtained by dividing the force composite yaw moment (Mgz_act) by the vehicle yaw inertia moment Iz. Therefore, Expression 4-7 represents a relationship that γdot_act matches Mgz_act / Iz.

  When the above equations 4-6 and 4-7 are used as simultaneous equations and Vy_act is eliminated, the following equation 4-8 is obtained.

γdot_act− (a21 / a11) * Accy_sensor_act
= Μ_act * ((a22− (a21 / a11) * a12s) * γ_act / Vx_act
+ (B2- (a21 / a11) * b1) * δf_act) ...... Formula 4-8

Here, as described above, when the vehicle 1 is traveling with δ1 = δ2 = 0 and the vehicle center-of-gravity skid angle βg is generated, the NSP generates all wheels 2-i (i = 1, 2). , 3, 4) means the point of application (action point) of the resultant force of the lateral force Fsuby_i (i = 1, 2, 3, 4). Therefore, in the dynamic model of the vehicle 1 represented by the equation 4-3, the vehicle center-of-gravity / NSP distance Lnsp, which is the distance between the center of gravity of the vehicle 1 and the NSP, and the cornering power CPf0, The relationship of the following expression 4-9 is established with CPr0.

Lnsp =-(Lf * CPf0-Lr * CPr0) / (CPf0 + CPr0) ...... Formula 4-9

Furthermore, the following expression 4-10 is obtained from the expression 4-9 and the definitions of a11 and a21 shown in the proviso of the expression 4-2.

a21 / a11 = -Lnsp * m / Iz Equation 4-10

Then, by applying the expression 4-10 to the left side of the expression 4-8, the expression 4-8 can be rewritten as the following expression 4-11.

Iz * γdot_act + Lnsp * m * Accy_sensor_act = μ_act * p (γ_act, δf_act, Vx_act)
... Formula 4-11
However,
p (γ_act, δf_act, Vx_act)
= Iz * ((a22− (a21 / a11) * a12s) * γ_act / Vx_act
+ (B2− (a21 / a11) * b1) * δf_act) …… Equation 4-12

Both sides of Expression 4-11 mean the actual moment around the yaw axis at NSP (actual NSP yaw moment Mnsp_act). That is, the actual NSP yaw moment Mnsp_act coincides with the left side and the right side of Equation 4-11 as shown in the following Equations 4-13a and 4-13b.

Mnsp_act = Iz * γdot_act + Lnsp * m * Accy_sensor_act ...... Formula 4-13a
Mnsp_act = μ_act * p (γ_act, δf_act, Vx_act) ...... Formula 4-13b

Equation 4-13a is an external force moment (a moment obtained by inverting the sign of the actual inertial force moment) that balances the actual inertial force moment (moment component of the actual inertial force) around the yaw axis generated by the NSP by the movement of the vehicle 1. ) Represents the actual NSP yaw moment Mnsp_act. The first term on the right side of Equation 4-13a is an external force moment that balances the actual inertial moment around the yaw axis generated at the center of gravity of the vehicle 1 by the movement of the vehicle 1 (that is, the actual total road surface reaction force combined yaw moment). Mgz_total_act). The second term on the right side of Equation 4-13b is the actual translational inertial force in the Y-axis direction of the vehicle body coordinate system generated at the center of gravity of the vehicle 1 due to the movement of the vehicle 1 (the translational force component of the actual inertial force). ) (Ie, the actual total road surface reaction force combined translational force vector ↑ Fg_total_act, Y-axis direction component Fgy_total_act of the vehicle body coordinate system) corresponds to the moment (= Lnsp * Fgy_total_act) generated around the yaw axis in NSP .

  Further, the expression 4-13b is obtained as an actual NSP around the yaw axis acting on the NSP by the resultant force of the actual road surface reaction force acting on each wheel 2-i from the road surface depending on the actual road surface friction coefficient μ_act. This is a representation of the yaw moment Mnsp_act. Note that p (γ_act, δf_act, Vgx_act) defined by Expression 4-12 is the ratio of the increase amount of Mnsp_act to the increase amount of μ_act (differential value of Mnsp_act by μact), as is apparent from Expression 4-13b. In other words, it has a meaning as sensitivity of Mnsp_act (hereinafter referred to as μ sensitivity) with respect to a change of μ_act. In other words, p (γ_act, δf_act, Vgx_act) is the actual NSP yaw moment Mnsp_act when μ_act = 1 (when the actual road surface friction coefficient μ_act matches the friction coefficient of the reference road surface). .

  Here, neither the right side of the equations 4-13a and 4-13b includes the actual vehicle gravity center side slip velocity Vgy_act or the actual road surface bank angle θbank_act. Therefore, it can be seen that the actual NSP yaw moment Mnsp_act is defined without depending directly on the actual vehicle center-of-gravity skid speed Vgy_act or the actual road surface bank angle θbank_act. More specifically, when a change in the actual vehicle center-of-gravity skid speed Vgy_act or a change in the actual road surface bank angle θbank_act occurs, the moment component of the first term on the right side of the equation 4-13a and the Although the moment component of the two terms changes, the change of these moment components basically occurs in opposite directions. For this reason, changes in the moment components of the first term and the second term of Expression 4-13a due to changes in Vgy_act or changes in θbank_act occur so as to cancel each other. As a result, the actual NSP yaw moment Mnsp_act is less likely to be affected by changes in Vgy_act or changes in θbank_act.

  As is clear from Equation 4-13b, the actual NSP yaw moment Mnsp_act does not directly depend on the values of Vgy_act and θbank_act in a situation where μ sensitivity p (γ_act, δf_act, Vx_act) is p ≠ 0. It can be seen that the actual road surface friction coefficient μ_act and μ sensitivity p change depending on the actual road surface friction coefficient μ_act and μ sensitivity p.

  If attention is paid to the expression 4-13a of the expressions 4-13a and 4-13b, the actual yaw angular acceleration γdot_act and the actual sensor-sensitive lateral acceleration Accy_sensor_act as the motion state quantity of the vehicle 1 are observed. Based on these observation values, the actual NSP yaw moment Mnsp_act value generated by the resultant force of the actual road surface reaction force acting on each wheel 2-i from the road surface (which depends on the actual road surface friction coefficient μ_act) is specified. I understand that I can do it. In this case, the right side of Expression 4-13a does not include the actual road surface friction coefficient μ_act, and does not include the actual vehicle center-of-gravity lateral acceleration Vgy_act and the actual road surface bank angle θbank_act. For this reason, the actual yaw angular acceleration γdot_act and the actual sensor-sensitive lateral acceleration Accy_sensor_act can be used without the actual road surface friction coefficient μ_act, actual vehicle center-of-gravity lateral acceleration Vgy_act, and actual road surface bank angle θbank_act. The observed value of the NSP yaw moment Mnsp_act can be obtained.

  Here, the yaw angular acceleration detected value γdot_sens has the meaning as the observed value of the actual yaw angular acceleration γdot_act, and the vehicle center-of-gravity lateral acceleration detected value Accy_sens has the meaning as the observed value of the actual sensor-sensitive lateral acceleration Accy_sensor_act. Therefore, a value calculated by an expression obtained by replacing γdot_act and Accy_sennsor_act on the right side of Expression 4-13a with γdot_sens and Accy_sens as the observed values is hereinafter referred to as an NSP yaw moment detected value Mnsp_sens. That is, Mnsp_sens is defined by the following equation 4-14.

Mnsp_sens = Iz * γdot_sens + Lnsp * m * Accy_sens ...... Formula 4-14

In this case, assuming that the yaw angular acceleration detection value γdot_sens and the vehicle center-of-gravity lateral acceleration detection value Accy_sens match the actual yaw angular acceleration detection value γdot_act and the actual sensor sensitive lateral acceleration Accy_sensor_act with high accuracy, Mnsp_act = Mnsp_sens. Therefore, the NSP yaw moment detected value Mnsp_sens as the observed value of the actual NSP yaw moment Mnsp_act can be calculated from the yaw angular acceleration detected value γdot_sens and the vehicle center-of-gravity lateral acceleration detected value Accy_sens by Equation 4-14. The NSP yaw moment detection value Mnsp_sens calculated in this way does not require an actual external force (actual road surface reaction force) value or an actual road surface friction coefficient μ_act acting on the vehicle 1, and the motion of the vehicle 1. It has a meaning as a value (detected value) of Mnsp estimated based on the observed value of the state quantity.

  Next, apart from the NSP yaw moment detected value Mnsp_sens, an estimated value of the road surface friction coefficient μ is used for the road surface reaction force acting on the wheels of the vehicle 1 on the model, based on an appropriate dynamic model of the vehicle 1. A process for estimating the value of the NSP yaw moment Mnsp generated by the resultant resultant road reaction force will be described.

  Here, in the present embodiment, the road surface reaction force estimated value is actually calculated by the vehicle model calculation means 24 using the friction characteristic model and the vehicle motion model as described above. Then, from the estimated value of the road surface reaction force, the value of the NSP yaw moment Mnsp can be estimated as will be described later. However, in this description, for the purpose of explaining the estimation principle of the road surface friction coefficient μ, for convenience, vehicle model calculation means (hereinafter referred to as explanation vehicle model calculation means) different from the vehicle model calculation means 24 is used. It is assumed that, using the dynamic model of the vehicle 1 represented by Formula 4-3, the estimation calculation process of the motion state amount of the vehicle 1 and the road surface reaction force is sequentially executed at a predetermined calculation process cycle.

  In this case, the explanatory vehicle model calculation means includes a front wheel steering angle detection value δf_sens, a yaw rate detection value γ_sens, a vehicle center of gravity longitudinal speed estimation value Vgx_estm as a vehicle speed observation value, a road surface friction coefficient estimation value μ_estm in each calculation processing cycle. , And the latest value (previous value or current value) of the estimated road bank angle θbank_estm are input as observed values of δf_act, γ_act, Vgx_act, μ_act, and θbank_act on the right side of Equation 4-3, respectively. Here, Vgx_estm, μ_estm, and θbank_estm mean observed values obtained by any appropriate method. In addition, the values of the parameters a11, a12s, a21, a22, b1, and b2 in the equation 4-3 are set in advance.

  And the vehicle model calculation means for description shall perform the estimation calculation process shown below. That is, the explanatory vehicle model calculation means calculates the vehicle center-of-gravity skid speed according to the following equation 5-1, in which an actual value such as γ_act in the first row of the equation 4-3 is replaced with an estimated value or a detected value. A vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm, which is an estimated value of the temporal change rate (differential value) of Vgy, is calculated.

Vgdot_y_estm = μ_estm * a11 * Vgy_estm_p / Vgx_estm
+ Μ_estm * a12s * γ_sens / Vgx_estm + μ_estm * b1 * δf_sens
−Vgx_estm * γ_sens−g * sin (θbank_estm)
... Formula 5-1

The vehicle center-of-gravity skid speed estimated value Vgy_estm_p required for the calculation of the first term on the right side of Equation 5-1 is the previous value as the latest value of Vgy_estm that has already been calculated by the vehicle model calculation means for explanation.

  In this case, the fourth term and the fifth term are removed from the right side of Expression 5-1, and the vehicle body of the translational force vector acting on the center of gravity of the vehicle 1 by the resultant force of the road surface reaction force of each wheel 2-i. It has a meaning as a value obtained by dividing the estimated value of the horizontal component of 1B (that is, the estimated value Fgy_total_estm of the Y-axis direction component of the total road surface reaction force combined translational force vector ↑ Fg_total) by the vehicle mass m. The fourth term on the right side is an estimated value of acceleration generated at the center of gravity of the vehicle 1 due to the centrifugal force accompanying the turning motion of the vehicle 1, and the fifth term is the lateral acceleration of the vehicle body 1B in the gravitational acceleration. It means the estimated value of the acceleration component in the direction.

  Therefore, Formula 5-1 calculates Fgy_total_estm / m based on μestm, Vgy_estm_p, Vgx_estm, γ_sens, and δf_sens, and the acceleration of centrifugal force acting on the center of gravity of the vehicle 1 from the calculated value of Fgy_total_estm / m The vehicle center-of-gravity skid speed change rate is subtracted from the estimated value (= Vgx_estm * γ_sens) of the vehicle and the estimated value of the acceleration component in the lateral direction of the vehicle body 1B (= g * sin (θbank_estm)). The process which calculates estimated value Vgdot_y_estm is shown.

  The explanatory vehicle model calculation means then calculates the integral calculation of Vgdot_y_estm from the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm and the previous value Vgy_estm_p of the vehicle center-of-gravity skid speed estimated value obtained as described above. Thus, a new vehicle center-of-gravity skid speed estimated value Vgy_estm (current value) is calculated. Note that ΔT in Expression 5-2 is a calculation processing cycle of the explanatory vehicle model calculation means.

Vgy_estm = Vgy_estm_p + Vgdot_y_estm * ΔT ...... Formula 5-2

Vgy_estm calculated in this way is used to calculate a new vehicle center-of-gravity skid speed change rate Vgdot_y_estm in the next calculation processing cycle. The Vgy_estm calculated by the explanatory vehicle model calculating means corresponds to the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by the vehicle motion estimating unit 24d of the vehicle model calculating means 24 described above.

  Further, the explanatory vehicle model calculation means calculates a sensor-sensitive lateral acceleration estimated value Accy_sensor_estm, which is an estimated value of the actual acceleration to which the lateral acceleration sensor 15 of the vehicle 1 is sensitive (that is, the actual sensor-sensitive lateral acceleration Accy_sensor_act), using the following equation 5-3: (In other words, by calculation from the first term to the third term on the right side of Equation 5-1).

Accy_sensor_estm = μ_estm * a11 * Vgy_estm_p / Vgx_estm
+ Μ_estm * a12s * γ_sens / Vgx_estm + μ_estm * b1 * δf_sens
... Formula 5-3

Here, supplementing this equation 5-3, as is clear from the equation 4-5, the following equation 5-4 is established.

Accy_sensor_estm = Vgdot_y_estm + Vgx_estm * γ_sens + g * sin (θbank_estm)
... Formula 5-4

As is clear from Expression 5-4 and Expression 5-1, the right side of Expression 5-4 matches the sum of the first to third terms on the right side of Expression 5-1. Therefore, the sensor-sensitive lateral acceleration estimated value Accy_sensor_estm can be calculated by the equation 5-3.

  Further, the right side of the equation 5-3 is an estimated value of the lateral component of the vehicle body 1B in the translational force vector acting on the center of gravity of the vehicle 1 by the resultant force of the road surface reaction force of each wheel 2-i (that is, all It has a meaning as a value obtained by dividing the estimated value Fgy_total_estm of the Y-axis direction component of the road surface reaction force combined translational force vector ↑ Fg_total by the vehicle mass m. Therefore, Expression 5-3 shows processing for calculating Fgy_total_estm / m based on μestm, Vgy_estm_p, Vgx_estm, γ_sens, and δf_sens, and obtaining the calculated Fgy_total_estm / m as Accy_sensor_estm.

  Further, the explanatory vehicle model calculation means calculates the yaw angular acceleration γdot by the following equation 5-5 in which an actual value such as γ_act in the equation in the second row of the equation 4-3 is replaced with an estimated value or a detected value. The yaw angular acceleration estimated value γdot_estm, which is the estimated value of the temporal change rate (differential value) of, is calculated.

γdot_estm = μ_estm * a21 * Vgy_estm_p / Vgx_estm
+ Μ_estm * a22 * γ_sens / Vgx_estm + μ_estm * b2 * δf_sens
... Formula 5-5

The right side of the equation 5-5 represents an estimated value of the moment about the yaw axis acting on the center of gravity of the vehicle 1 by the resultant force of the road surface reaction force of each wheel 2-i (that is, the total road surface reaction force combined yaw moment estimated value Mgz_estm ) Is divided by the vehicle yaw moment of inertia Iz. Therefore, Expression 5-5 indicates a process of calculating Mgz_estm / Iz based on μestm, Vgy_estm_p, Vgx_estm, γ_sens, and δf_sens, and obtaining the calculated Mgz_estm / Iz value as the yaw angular acceleration estimated value γdot_estm.

  Here, Equations 5-3 and 5-5 are used as simultaneous equations, Vgy_estm is eliminated, and Equation 4-10 is applied to obtain Equation 5-6 below.

Iz * γdot_estm + Lnsp * m * Accy_sensor_estm
= Μ_estm * p (γ_sens, δf_sens, Vgx_estm) ...... Formula 5-6
However,
p (γ_sens, δf_sens, Vgx_estm)
= Iz * ((a22− (a21 / a11) * a12s) * γ_sens / Vgx_estm
+ (B2− (a21 / a11) * b1) * δf_sens) ...... Formula 5-7

Note that p (γ_sens, δf_sens, Vgx_estm) defined by Expression 5-7 means the value of μ sensitivity calculated from the observed values γ_sens, δf_sens, Vgx_estm of γ, δf, and Vgx. In the following description, the μ sensitivity p means p (γ_sens, δf_sens, Vgx_estm) defined by the equation 5-7 unless otherwise specified. More generally, the μ sensitivity p defined by Expression 5-7 is a value of μ sensitivity calculated by linear combination of γ_sens and δf_sens. In this case, in this linear combination, if the coefficients applied to γ_sens and δf_sens are set to A1 and A2 (p = A1 * γ_sens + A2 * δf_sens), A1 = Iz * ((a22− (a21 / a11 ) * A12s) / Vgx_estm, A2 = (b2− (a21 / a11) * b1) Therefore, the coefficients A1 and A2 have their ratio A2 / A1 as Vgx_estm as an observed value of the vehicle speed. In other words, it is a linear combination of γ_sens and δf_sens according to Equation 5-7: A2 / A1 is a coefficient set so that it changes in proportion to Vgx_estm. Are the observed values (detected values) γ_sens, δf_sens, Vgx_estm as the values of γ_act, δf_act, Vgx_act when the road surface friction coefficient μ_act is assumed to be a constant value in the linear two-wheel vehicle model of Equation 4-3. The value of μ sensitivity p calculated by the linear combination is compared with the value of the actual NSP yaw moment Mnsp_act specified using It said to be a linear combination constructed so as to be.

  Supplementally, in the present embodiment, as described above, the yaw rate estimated value γ_estm is determined so as to match or substantially match the yaw rate detected value γ_sens. Therefore, an expression obtained by replacing γ_sens on the right side of Expression 5-7 with γ_estm may be used as a defining expression for obtaining the value of μ sensitivity p.

  Both sides of the above equation 5-6 represent an NSP yaw moment estimated value Mnsp_estm that is an estimated value of the moment around the yaw axis at the NSP (moment value on the model based on the equation 4-3). means. That is, the NSP yaw moment estimated value Mnsp_estm coincides with the left side and the right side of Equation 5-6 as shown in Equations 5-8a and 5-8b below.

Mnsp_estm = Iz * γdot_estm + Lnsp * m * Accy_sensor_estm ...... Formula 5-8a
Mnsp_estm = μ_estm * p (γ_sens, δf_sens, Vgx_estm) ...... Formula 5-8b

Expression 5-8a is an NSP yaw as an estimated value of a moment (moment obtained by reversing the sign of the inertial force moment) that balances the inertial force moment generated around the yaw axis at the NSP by the movement of the vehicle 1 on the model. This is a representation of the moment estimated value Mnsp_estm. Equation 5-8b is an NSP as an estimate of the moment around the yaw axis generated by the NSP by the resultant force of the road surface reaction force of each wheel 2-i depending on μ_estm (the resultant force of the road surface reaction force on the model). The yaw moment estimated value Mnsp_estm is expressed.

  In this case, the NSP yaw moment estimated value Mnsp_estm calculated by the expression 5-8b of the expressions 5-8a and 5-8b is calculated depending on the road surface friction coefficient estimated value μ_estm. Mnsp_estm reflects the influence of the error of the road surface friction coefficient estimated value μestm. Further, the right side of Expression 5-8b does not directly include the vehicle center-of-gravity lateral acceleration estimated value Vgy_estm or the road bank angle estimated value θbank_estm. For this reason, the NSP yaw moment estimated value Mnsp_estm calculated by Equation 5-8b is affected by the error of the vehicle center-of-gravity lateral acceleration estimated value Vgy_estm and the road bank angle estimated value θbank_estm, as described for the actual NSP yaw moment Mnsp_act. Will not be directly received.

  Therefore, the vehicle model calculation means for explanation calculates the NSP yaw moment estimated value Mnsp_estm by Expression 5-8b. The NSP yaw moment estimated value Mnsp_estm calculated in this way can be generalized. Based on the dynamic model of the vehicle 1, the estimated value of Mnsp_act calculated depending on μ_estm (more specifically, (Mnsp_act estimated value calculated assuming that μ_estm is accurate).

  The above is the processing of the explanatory vehicle model calculation means. Supplementally, in the vehicle model calculation means for explanation described above, for convenience of explanation of the estimation principle of the road surface friction coefficient μ, the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm, the vehicle center-of-gravity skid speed estimated value Vgy_estm, the yaw angular acceleration estimated value γdot_estm The sensor-sensitive lateral acceleration estimated value Accy_sensor_estm is calculated. On the premise of the dynamic model (linear two-wheel vehicle model) represented by the equation 4-3, the NSP yaw moment estimated value by the equation 5-8b. In calculating Mnsp_estm, Vgdot_y_estm, Vgy_estm, γdot_estm, and Accy_sensor_estm are not necessary, as is apparent from 5-7 and 5-8b. When the dynamic model represented by the equation 4-3 is assumed, the calculation result value on the right side of the equation 5-8a and the calculation result on the right side of the equation 5-8b are the same value. Therefore, Mnsp_estm may be calculated by Expression 5-8a.

  Next, a method for estimating the road surface friction coefficient μ based on the NSP yaw moment detected value Mnsp_sens obtained by the equation 4-14 and the NSP yaw moment estimated value Mnsp_estm calculated by the equation 5-8b will be considered. . As described above, Mnsp_sens is an observed value (γdot_sens, Accy_sens) of the motion state quantity of the vehicle 1 without requiring the value of the road surface reaction force acting on the vehicle 1 as an external force or the value of the road surface friction coefficient μ. It has a meaning as an observed value (detected value) of Mnsp_act obtained based on. Mnsp_estm has a meaning as an observed value (estimated value) of Mnsp_act calculated using μ_estm based on the dynamic model of the vehicle 1. Therefore, the deviation between Mnsp_sens and Mnsp_estm is considered to have a correlation with the error of μ_estm with respect to μ_act.

  Here, the yaw rate detection value γ_sens, the yaw angular acceleration detection value γdor_sens, the front wheel rudder angle detection value δf_sens, the vehicle center-of-gravity longitudinal acceleration estimation value Vgx_estm (vehicle speed estimation value), and the vehicle center-of-gravity lateral acceleration detection value Accy_sens are respectively the actual yaw rate γ_act, It is assumed that the actual yaw angular acceleration γdot_act, the actual front wheel steering angle detection value δf_act, the actual vehicle center-of-gravity longitudinal velocity Vgx_act, and the actual sensor-sensitive lateral acceleration Acc_sensor_act are accurately matched. At this time, the following equation 6-1 is obtained from the equation 4-11.

Iz * γdot_sens + Lnsp * m * Accy_sens = μ_act * p (γ_sens, δf_sens, Vgx_estm)
... Formula 6-1

Then, the following expression 6-2 is obtained from the expression 6-1 and the expressions 4-14, 5-6, and 5-8b.

Mnsp_sens−Mnsp_estm = (Iz * γdot_sens + Lnsp * m * Accy_sens)
-(Iz * γdot_estm + Lnsp * m * Accy_sensor_estm)
= (Μ_act−μ_estm) * p (γ_sens, δf_sens, Vgx_estm)
... Formula 6-2

From Equation 6-2, in order to make the road surface friction coefficient estimated value μ_estm coincide with the actual road surface friction coefficient μ_act, μ_estm is set so that Mnsp_estm coincides with Mnsp_sens in a situation where p (γ_sens, δf_sens, Vgx_estm) ≠ 0. It will be sufficient to determine. More generally, this is an actual NSP calculated using a dynamic model (dynamic model depending on the road surface friction coefficient estimated value μ_estm) including the friction characteristics of each wheel 2-i of the vehicle 1. The estimated value of yaw moment Mnsp_act (NSP yaw moment estimated value Mnsp_estm) is used to detect the detected yaw angular acceleration γdot_sens and the vehicle center-of-gravity lateral acceleration detected value Accy_sens (= sensor-sensitive lateral acceleration Accy_sensor). This means that the road surface friction coefficient estimated value μestm to be applied to the dynamic model should be determined so as to match the estimated value (NSP yaw moment detected value Mnsp_sens) of the actual NSP yaw moment Mnsp_act calculated from To do.

  In this case, p (γ_sens, δf_sens, Vgx_estm) on the right side of Expression 6-2 does not include the vehicle center-of-gravity skid speed estimated value Vgy_estm and the road bank angle estimated value θbank_estm, as is apparent from Expression 5-7. Therefore, in the situation where p (γ_sens, δf_sens, Vgx_estm) ≠ 0, the value of the deviation between Mnsp_sens and Mnsp_estm (the left side of Equation 6-2) is the correlation with the deviation between μ_act and μ_estm (ie, the error of μ_estm). Is considered high. In other words, in a situation where p (γ_sens, δf_sens, Vgx_estm) ≠ 0, the deviation between Mnsp_sens and Mnsp_estm is considered to be mainly caused by the error of μ_estm. Therefore, if the road surface friction coefficient estimated value μ_estm is determined based on the equation 6-2, it is possible to suppress the influence of errors of the vehicle center-of-gravity skid speed estimated value Vgy_estm and the road surface bank angle estimated value θbank_estm. Thus, it is considered that the actual road surface friction coefficient μ_act can be estimated. Therefore, the μ estimation means 26 in the present embodiment calculates the road surface friction coefficient estimated value μ_estm based on the equation 6-2.

  In order to determine the road surface friction coefficient estimated value μ_estm so that Mnsp_estm coincides with Mnsp_sens in the situation where p (γ_sens, δf_sens, Vgx_estm) ≠ 0 based on Equation 6-2 as described above, for example, It is conceivable to determine the road surface friction coefficient estimated value μ_estm so as to satisfy Expression 6-3.

Mnsp_sens = μ_estm * p (γ_sens, δf_sens, Vgx_estm) ...... Formula 6-3

However, in this case, an excessive change in the road surface friction coefficient estimated value μ_estm tends to occur due to errors in Mnsp_sens, γ_sens, Δf_sens, and Vgx_estm. In particular, when the value of p (γ_sens, δf_sens, Vgx_estm) is close to “0”, it is difficult to ensure the reliability and stability of the road surface friction coefficient estimated value μ_estm obtained based on Expression 6-3. It is.

  Therefore, the μ estimation means 26 in the present embodiment is based on the NSP yaw moment detected value Mnsp_sens obtained from the observed value of the motion state quantity of the vehicle 1 and the road surface reaction force estimated depending on the road surface friction coefficient estimated value μ_estm. In order to converge the deviation to “0” (so that Mnsp_estm converges to Mnsp_sens) by feedback calculation processing according to the deviation from the NSP yaw moment estimated value Mnsp_estm required for Then, the value of μestm is updated according to the increase / decrease operation amount. Thus, μestm is sequentially calculated so that the road surface friction coefficient estimated value μestm converges to the actual road surface friction coefficient μ_act (constantly coincides with μ_act). Hereinafter, the deviation (= Mnsp_sens−Mnsp_estm) between Mnsp_sens and Mnsp_estm is referred to as NSP yaw moment estimation error Mnsp_err.

  In this case, as is clear from the equation 6-2, the NSP yaw moment estimation error Mnsp_err is proportional to the μ sensitivity p. As the μ sensitivity p is closer to “0”, the sensitivity of Mnsp_err to the error of μ_estm (the magnitude of the ratio of change in Mnsp_err to the change in error of μ_estm) decreases. Therefore, in this embodiment, in order to ensure the reliability and stability of μ_estm, the gain value that is the ratio of the change in the amount of increase / decrease in μ_estm with respect to the change in Mnsp_err (in other words, Mnsp_err is converged to “0”). The feedback gain of the feedback calculation process) is changed according to the μ sensitivity p.

  The above is the basic estimation principle of the road surface friction coefficient μ in the present embodiment.

  Based on the basic estimation principle of the road surface friction coefficient μ described above, the processing of the μ estimation means 26 in the present embodiment will be described with reference to FIGS. 11 and 12.

  As shown in the block diagram of FIG. 11, the μ estimator 26 functions as the Mnsp_sens calculator 26a that calculates the NSP yaw moment detected value Mnsp_sens, the Mnsp_estm calculator 26b that calculates the NSP yaw moment estimated value Mnsp_estm, Mnsp_err calculation unit 26c for calculating NSP yaw moment estimation error Mnsp_err, μ sensitivity calculation unit 26d for calculating μ sensitivity p (γ_sens, δf_sens, Vgx_estm), NSP yaw moment estimation error Mnsp_err and μ sensitivity p (γ_sens, δf_sens, Vgx_estm), a friction coefficient increase / decrease operation amount determination unit 26e that determines an increase / decrease operation amount Δμ of the road surface friction coefficient μ, and a friction coefficient estimate value update that updates the road surface friction coefficient estimate value μ_estm according to the increase / decrease operation amount Δμ. 26f.

  Then, the μ estimation means 26 sequentially determines the road surface friction coefficient estimated value μ_estm by executing the processing of the flowchart of FIG.

  That is, the μ estimating means 26 executes the processing of the Mnsp_sens calculating unit 26a in S118-1 to calculate the NSP yaw moment detected value Mnsp_sens. Specifically, the Mnsp_sens calculation unit 26a includes the motion state quantity of the vehicle 1 related to the inertial force moment that balances the NSP yaw moment Mnsp among the observation target quantity detection values generated by the observation target quantity detection unit 22 in S100. Mnsp_sens is calculated by performing the calculation of the right side of Equation 4-14 using the yaw angular acceleration detection value γdot_sens as the observed value and the vehicle center-of-gravity lateral acceleration detection value Accy_sens (sensor-sensitive lateral acceleration detection value). In this case, predetermined values set in advance are used as the value of the vehicle yaw inertia moment Iz, the value of the vehicle mass m, and the value of the vehicle center-of-gravity / NSP distance Lnsp necessary for the calculation of Expression 4-14. The first term on the right side of Equation 4-14 corresponds to the total road surface reaction force combined yaw moment detected value Mgz_total_sens, and m * Accy_sens in the second term corresponds to the total road surface reaction force combined lateral force detected value Fgy_total_sens. To do.

  Further, in S118-2, the μ estimating means 26 executes the processing of the Mnsp_estm calculating unit 26b to calculate the NSP yaw moment estimated value Mnsp_estm. Specifically, the Mnsp_estm calculating unit 26b calculates the total road surface reaction force combined lateral force estimated value Fgy_total_estm (total road surface reaction force combined translational force vector estimated value ↑ Fg_total_estm in the Y-axis direction) calculated by the vehicle model calculating unit 24 in S112. Component) and the total road surface reaction force composite yaw moment estimated value Mgz_total_estm, Mnsp_estm is calculated by the following equation 7-1.

Mnsp_estm = Mgz_total_estm + Lnsp * Fgy_total_estm ...... Formula 7-1

Next, in S118-3, the μ estimation means 26 executes the processing of the Mnsp_err calculation unit 26c to calculate the NSP yaw moment estimation error Mnsp_err. Specifically, the Mnsp_err calculating unit 26c calculates Mnsp_err by subtracting the NSP yaw moment estimated value Mnsp_estm calculated in S118-2 from the NSP yaw moment detected value Mnsp_sens calculated in S118-1.

  Further, the μ estimation means 26 executes the processing of the μ sensitivity calculation unit 26d in S118-4 to calculate the μ sensitivity p. Specifically, the μ sensitivity calculation unit 26d is obtained by the yaw rate detection value γ_sens and the front wheel steering angle detection value δf_sens generated by the observation target amount detection unit 22 in S100, and by the vehicle model calculation unit 24 in S114. The μ sensitivity p (γ_sens, δf_sens, Vgx_estm) is calculated from the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm by calculating the right side of the equation 5-7. In this case, predetermined values set in advance are used as the values of the vehicle inertia yaw moment Iz and the parameters a11, a12s, a21, a22, b1, and b2 necessary for the calculation of Expression 5-7.

  In this case, as is clear from Expression 5-7, the μ sensitivity p is obtained by linear combination of γ_sens and δf_sens. In this linear combination, the ratio between the coefficient applied to γ_sens and the coefficient applied to Δf_sens changes according to Vgx_estm.

  Next, the μ estimation means 26 executes the process of the friction coefficient increasing / decreasing manipulated variable determiner 26e in S118-5, and the NSP yaw moment estimated error Mnsp_err calculated in S118-3 and the μ calculated in S118-4. The friction coefficient increasing / decreasing manipulated variable Δμ is determined according to the sensitivity p. In this process, the friction coefficient increasing / decreasing manipulated variable Δμ is determined so that Mnsp_err converges to “0” (that is, Mnsp_estm converges to Mnsp_sens) by the feedback control law. In this case, a proportional law is used as the feedback control law, and Δμ is calculated by multiplying a certain gain value Gmu by Mnsp_err. In this case, Δμ is determined to be proportional to the product of Mnsp_err and the μ sensitivity p. As a result, the gain value Gmu (hereinafter, Gmu is referred to as a friction coefficient operation gain) representing the rate of change in Δμ with respect to the change in Mnsp_err is determined so as to change according to the μ sensitivity p.

  Specifically, in the present embodiment, the friction coefficient increasing / decreasing manipulated variable determiner 26e calculates Δμ by the following equation 7-2. Note that Kmu in Expression 7-2 is a predetermined positive value set in advance.

Δμ = Mnsp_err * Gmu
= Mnsp_err * (p (γ_sens, δf_sens, Vgx_estm) * Kmu)
...... Formula 7-2

That is, the friction coefficient increasing / decreasing manipulated variable determiner 26e is obtained by multiplying the μ sensitivity p calculated in S118-4 by the basic gain Kmu that is a preset positive predetermined value (= Kmu * p). A friction coefficient increasing / decreasing manipulated variable Δμ is determined by multiplying the friction coefficient operating gain Gmu by the NSP yaw moment estimation error Mnsp_err calculated in S118-3. In this case, the friction coefficient operating gain Gmu has the same polarity as the μ sensitivity p, and is determined so that the smaller the magnitude (absolute value) of the μ sensitivity p is, the smaller the magnitude (absolute value) of Gmu is. Will be.

  Next, in S118-6, the μ estimating means 26 executes the process of the friction coefficient estimated value updating unit 26f, and updates the road surface friction coefficient estimated value μ_estm. Specifically, the friction coefficient estimated value updating unit 26f adds the friction coefficient increasing / decreasing manipulated variable Δμ calculated in S118-5 to the previous value μ_estm_p of the road surface friction coefficient estimated value, thereby obtaining the road surface friction coefficient estimated value μ_estm. Update from the previous value μ_estm_p to obtain a new road surface friction coefficient estimated value μ_estm (current value μ_estm). In other words, this process is a process of obtaining the road surface friction coefficient estimated value μ_estm by integrating Δμ.

The above is the details of the processing of the μ estimation means 26 in the present embodiment.
* Only p107 (the last page of the embodiment) is dedicated to this case. In the present embodiment described above, especially when calculating the vehicle center-of-gravity skid speed estimated value Vgy_estm, the change in the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut is In situations where there is a high probability that it has occurred due to actual side-slip movement changes (Accy_err_lowcut and α2 * γdot_err_lowcut have the same polarity), the necessary correction amount Vgdot_y_cmpn, which is the same as Accy_err_lowcut, is high-cut. By passing through the filter 24d22 and the gain multiplier 24, the skid speed correction manipulated variable Vgy_cmpn is determined. Then, on the vehicle model, a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict as a value of the state amount of the skid motion of the vehicle 1 generated by the external force of the total road surface reaction force combined lateral force estimated value Fgy_total_estm by Vgy_cmpn. Is determined as the vehicle center-of-gravity skid speed estimated value Vgy_estm. As a result, the accuracy of the vehicle center-of-gravity skid speed estimated value Vgy_estm in the transition period in a situation where the side-slip motion of the vehicle 1 changes due to a change in the actual road surface friction coefficient μ_act or the like is obtained. Than can be raised.

  On the other hand, a situation where the change in the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut is likely to have occurred due to a change in the actual road bank angle θbank_act (a situation where Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities) Then, the required side slip velocity change rate correction amount Vgdot_y_cmpn has the same polarity as Accy_err_lowcut and is closer to “0” than Accy_err_lowcut or becomes “0”. Therefore, as a result, the skid speed correction manipulated variable Vgy_cmpn in this case is determined to be a value closer to “0” than the value obtained by passing Accy_err_lowcut through the high cut filter 24d22 and the gain multiplier 24d23, or “ 0 "will be determined. For this reason, when Accy_err_lowcut changes due to the change in the actual road bank angle θbank_act, the correction of the vehicle center of gravity side slip velocity model estimated value Vgy_predict is suppressed, and an inappropriate vehicle center of gravity side slip velocity estimated value Vgy_estm is calculated. Can be prevented. As a result, the reliability and stability of the vehicle center-of-gravity skid speed estimated value Vgy_estm can be improved.

  Further, the vehicle center-of-gravity skid speed estimated value Vgy_estm obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict using Vgy_cmpn is a process for calculating the vehicle center-of-gravity skid speed model estimated value Vgy_predict and a process for calculating the road surface friction coefficient estimated value μ_estm. Therefore, the frequency characteristic of the transfer function of the arithmetic processing system from the output of the lateral acceleration sensor 15 to the side slip speed correction manipulated variable Vgy_cmpn is the actual vehicle center-of-gravity longitudinal speed Vgx_act (actual vehicle speed) or It is possible to avoid the influence of the change in the actual road surface friction coefficient μ_act. As a result, the convergence response of the estimated vehicle center-of-gravity skid velocity Vgy_estm to changes in the actual vehicle center-of-gravity skid velocity Vgy_act is kept constant regardless of changes in the actual vehicle center-of-gravity longitudinal velocity Vgx_act (actual vehicle speed) and actual road surface friction coefficient μ_act. be able to.

  The present embodiment is an embodiment of the fourth invention, and Vgy_cmpn is obtained using Accy_err_lowcut and γdot_err_lowcut. However, if the vehicle center-of-gravity lateral acceleration detection value Accy_sens or the yaw angular acceleration detection value γdot_sens does not include a steady offset component or the offset component is sufficiently small, the filter 24d10 24d11 may be omitted, and Vgy_cmpn may be obtained in the same manner as described above using Accy_err and γdot_err instead of Accy_err_lowcut and γdot_err_lowcut. By doing in this way, embodiment of the said 3rd invention will be constructed | assembled.

  The gain multiplier 24d23 may be incorporated in the high cut filter 24d22. That is, the high cut filter 24d22 may be configured as a filter whose transfer function is represented by T4 / (1 + T4 * S). In this case, the gain multiplication unit 24d23 is not necessary.

  Further, the filter 24d22 may be a band pass characteristic filter having a low cut characteristic in addition to a high cut characteristic. Similarly, the filters 24d10 and 24d11 may be band-pass filters that have a high cut characteristic in addition to the low cut characteristic.

  Further, the process of passing the required side slip velocity change rate correction amount Vgdot_y_cmpn through the high cut filter 24d22 and the gain multiplier 24d23 is equivalent to the process of passing Vgdot_y_cmpn through the low cut filter (first-order low cut filter of the time constant T4) and the integrator. Therefore, a low cut filter and an integrator may be provided instead of the high cut filter 24d22 and the gain multiplication unit 24d23. However, in this case, calculation errors associated with the integration calculation are likely to accumulate in the integrator. On the other hand, when the side slip velocity change rate necessary correction amount Vgdot_y_cmpn is passed through the high cut filter 24d22 and the gain multiplication unit 24d23 as in the above embodiment, without accumulating calculation errors in the integrator, A skid speed correction manipulated variable Vgy_cmpn can be obtained.

  Further, the weighting factors α1 and α2 in the linear combination value (= α1 * Accy_err_lowcut + α2 * γdot_err_lowcut) of Accy_err_lowcut and γdot_err_lowcut may be set to values different from those in the present embodiment. For example, the Lnsp homopolarity coefficient α2 may be set to a value closer to “0” than Iz / (m * Lnsp). Further, for example, a value obtained by multiplying both values (“1”, Iz / (m * Lnsp)) of the weighting factors α1 and α2 in the present embodiment by an arbitrary constant value other than “0” is renewed as a weighting factor. You may make it use as a value of (alpha) 1 and (alpha) 2.

  In the present embodiment, when Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities, α2 * γdot_err_lowcut has a different polarity from Accy_err_lowcut, and the absolute value of α2 * γdot_err_lowcut is smaller than the absolute value of Accy_err_lowcut. The linear combination value SUM is set as the side slip velocity change rate necessary correction amount Vgy_cmpn. However, when Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities, Vgy_cmpn is always set to “0”. Good.

  Further, instead of the processing in the broken line frame of the block diagram of FIG. 10, the side slip velocity change rate necessary correction amount Vgdot_y_cmpn may be obtained by executing the processing shown in the flowchart of FIG.

  In this process, the vehicle motion estimation unit 24d first calculates a linear combination value SUM (= α1 * Accy_err_lowcut + α2 * γdot_err_lowcut) between the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angular acceleration deviation filtering value γdot_err_lowcut in S114-11. calculate. In this example, α1 = 1 and α2 = Iz / (m * Lnsp).

  Next, the vehicle motion estimation unit 24d determines whether or not Accy_err_lowcut ≧ 0 in S114-12. At this time, if the determination result in S114-12 is affirmative, that is, if Accy_err_lowcut is positive or “0”, the vehicle motion estimation unit 24d further performs the linear combination value SUM obtained in S114-11. Is determined in S114-13 whether SUM ≧ Accy_err_lowcut. Here, the positive determination result in S114-13 means that α2 * γdot_err_lowcut has the same polarity as Accy_err_lowcut (≧ 0) or is “0”.

  If the determination result in S114-12 is negative, that is, if Accy_err_lowcut is negative, the vehicle motion estimation unit 24d further determines whether or not the SUM obtained in S114-11 is SUM <Accy_err_lowcut. Is determined in S114-14. Here, the positive determination result in S114-14 means that α2 * γdot_err_lowcut has the same polarity as Accy_err_lowcut (<0).

  If the determination result in S114-13 or the determination result in S114-14 is affirmative, the vehicle motion estimation unit 24d determines that the side slip speed change rate required correction amount Vgdot_y_cmpn is the value of Accy_err_lowcut in S114-15. Set.

  On the other hand, if the determination result in S114-13 is negative, the vehicle motion estimation unit 24d further determines in S114-16 whether SUM <0. Similarly, if the determination result in S114-14 is negative, the vehicle motion estimation unit 24d further determines in S114-17 whether SUM ≧ 0. Here, that the determination result of S114-16 is affirmative or that the determination result of S114-17 is affirmation means that the linear combination value SUM is not the same polarity as Accy_err_lowcut (SUM = 0 or (Accy_err_lowcut = 0 is included). In this case, except for the case where Accy_err_lowcut = 0, α2 * γdot_err_lowcut is opposite in polarity to Accy_err_lowcut.

  If the determination result in S114-16 or S114-17 is affirmative, the vehicle motion estimation unit 24d sets “0” as the value of the required side slip speed change rate correction amount Vgdot_y_cmpn in S114-19. Set. If the determination result in S114-16 or S114-17 is negative, in S114-18, the vehicle motion estimation unit 24d sets SUM as the value of the required side slip velocity change rate correction amount Vgdot_y_cmpn. .

  According to the processing of the flowchart of FIG. 13 described above, when α2 * γdot_err_lowcut has the same polarity as Accy_err_lowcut, or when γdot_err_lowcut = 0, Accy_err_lowcut is set as the value of Vgdot_y_cmpn as it is. When α2 * γdot_err_lowcut is opposite in polarity to Accy_err_lowcut, or when Accy_err_lowcut is “0”, “0” or a linear combination value SUM is set as the value of Vgdot_y_cmpn. As described above, the same Vgdot_y_cmpn as in the case of executing the process shown in the block diagram of FIG. 10 is obtained by the process of the flowchart of FIG. That is, the process of the flowchart of FIG. 13 is equivalent to the process in the broken line frame of the block diagram of FIG.

  Supplementally, when the processing of the flowchart of FIG. 13 is performed, the correction basic value determining means in the present invention is realized by the processing of this flowchart. In this case, the linear combination value calculation means in the present invention is realized by the processing of S114-11 in FIG.

  The vehicle motion estimator 24d obtains Vgdot_x_estm, Vgx_estm, Vgx_predict, Vgdot_y_estm, Vgy_estm, Vgy_predict, γ_estm, γ_predict, and Accy_estm as vehicle motion state estimated values (including model estimated values). Thus, other vehicle motion state quantity estimated values may be obtained. For example, when the vehicle gravity center side slip angle βg is controlled using the estimated value of the vehicle motion state quantity, the estimated value of the vehicle center of gravity slip angle βg_estm is used as the estimated value of one state quantity of the side slip movement of the vehicle 1. May be calculated. In this case, the vehicle center-of-gravity skid angle estimated value βg_estm can be calculated by the following equation 1-26 from the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm and the vehicle center-of-gravity skid speed estimated value Vgy_estm obtained as described above.

βg_estm = tan ⁻¹ (Vgy_estm / Vgx_estm) ...... Formula 1-26

Alternatively, for example, a model estimated value of the vehicle center-of-gravity skid angle βg is obtained by an expression in which Vgy_estm on the right side of the expression 1-26 is replaced with the vehicle center-of-gravity skid speed model estimated value Vgy_predict. By adding the value (= Vgy_cmpn / Vgx_estm) obtained by dividing the calculated side-slip speed correction manipulated variable Vgy_cmpn by the vehicle center of gravity longitudinal speed estimated value Vgx_estm (where | Vgy_cmpn | is smaller than | Vgx_estm |) The vehicle center-of-gravity skid angle estimated value βg_estm may be obtained. In such a case, the model estimated value of the vehicle center-of-gravity skid angle βg corresponds to the skid motion state model value in the present invention, and Vgy_cmpn / Vgx_estm corresponds to the correction operation amount in the present invention.

  When obtaining βg_estm, the actual vehicle speed is detected based on the wheel speed detection value Vw_i_sens (i = 1, 2, 3, 4) instead of the vehicle center-of-gravity longitudinal speed estimation value Vgx_estm in any of the above methods. The wheel speed selection detection value Vw_i_sens_select as a value may be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, a part of the processing of the vehicle model calculation means 24 (specifically, processing of the vehicle motion estimation unit 24d (processing of S114 in FIG. 4) and processing of the wheel traveling speed vector estimation unit 24e (in FIG. 4). Only the processing of S104) is different from the first embodiment.

  In the first embodiment, in each calculation processing cycle of the control device 20, the vehicle model calculation means 24 causes the wheel traveling speed vector estimated value ↑ Vi_estm (i = 1, 2, 3, 4) or the vehicle center-of-gravity skid speed model estimation. When calculating the current value of the value Vgy_predict, the past calculated value of the vehicle center of gravity skid speed model estimated value Vgy_predict (previous value) is used instead of the past calculated value of the vehicle center of gravity skid speed estimated value Vgy_estm (previous value, etc.) doing.

  On the other hand, in this embodiment, in this embodiment, the past calculated value (previous value) of the vehicle center-of-gravity skid speed estimated value Vgy_estm is fed back to the process of the vehicle motion estimating unit 24d and the process of the wheel traveling speed vector estimating unit 24e. In the process of calculating the current value of ↑ Vi_estm (i = 1, 2, 3, 4) and Vgy_predict, the previous value Vgy_estm_p of the vehicle center-of-gravity skid speed estimated value is used.

That is, in this embodiment, in S104 of FIG. 4, the wheel traveling speed vector estimation unit 24e replaces Vgy_predict_p on the right side of the expression 1-2 with the previous value Vgy_estm_p of the vehicle center-of-gravity skid speed estimation value. -2a, each wheel traveling speed vector estimated value ↑ Vi_estm (= (Vx_i_estm, Vy_i_estm) ^T ) is calculated.

↑ Vi_estm = (Vx_i_estm, Vy_i_estm) ^T
= (Vgx_estm_p, Vgy_estm_p) ^T
+ (− Py_i * γestm_p, Px_i * γestm_p) ^T ...... Equation 1-2a

Note that using Vgy_estm_p to determine ↑ Vi_estm in this way means that the vehicle center-of-gravity skid speed estimated value Vgy_estm is one of the motion state quantities of the vehicle 1 for specifying the slip of each wheel 2-i. This means using the past calculated value.

  In the present embodiment, in the calculation process of the vehicle center-of-gravity longitudinal speed change rate estimated value Vgdot_x_estm in the process of S114 of FIG. 4, the vehicle motion estimation unit 24d determines Vgy_predict_p on the right side of the expression 1-13a as the vehicle center of gravity. The current value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict is calculated by the following expression 1-13aa, which is replaced with the previous value Vgy_estm_p of the estimated skid speed value. That is, the vehicle motion estimator 24d calculates the vehicle center-of-gravity skid as the previous value Vgy_predict of the vehicle center-of-gravity skid velocity model estimated value as the previous value of the vehicle center-of-gravity skid velocity Vgy on the vehicle motion model as described below The current value of the vehicle center longitudinal velocity change rate estimated value Vgdpt_x_estm is calculated as the previous value Vgy_estm_p of the estimated speed value.

Vgdot_x_estm = Fgx_total_estm / m + Vgy_estm_p * γ_estm_p ...... Equation 1-13aa

Furthermore, in the calculation process of the vehicle center-of-gravity skid speed model estimated value Vgy_predict in the process of S114 of FIG. 4, the vehicle motion estimator 24d sets Vgy_predict_p on the right side of the equation 1-19 to the previous value of the vehicle center-of-gravity skid speed estimated value. The current value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict is calculated by the following expression 1-19a replaced with the value Vgy_estm_p. That is, the vehicle motion estimator 24d calculates the vehicle center-of-gravity skid speed estimated value calculated as described later, the previous value Vgy_predict of the vehicle center-of-gravity skid speed model estimated value as the previous value of the vehicle center-of-gravity skid speed Vgy on the vehicle motion model. The current value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict is calculated as the same value as the previous value Vgy_estm_p.

Vgy_predict = Vgy_estm_p + Vgdot_y_estm * ΔT ...... Equation 1-19a

In the present embodiment, in each calculation processing cycle of the control device 20, the vehicle motion estimation unit 24d performs the processing shown in the flowchart of FIG. The current value of the vehicle center-of-gravity skid speed estimated value Vgy_estm as a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated by −19a is calculated.

  However, in this case, in this embodiment, the processing of S114-1 to S114-4 in FIG. 9 is the same as that of the first embodiment. On the other hand, in the present embodiment, a part of the processing of S114-5 is different from the first embodiment. That is, in this embodiment, the process of S114-5 is performed by the process shown in the block diagram of FIG. 14, for example. In FIG. 14, the same reference numerals as those in FIG. 10 are assigned to the same processing units as those in the block diagram of FIG.

  In the process of the block diagram of FIG. 14, the process combining the low-cut filters 24d10 and 24d11 and the process within the broken line frame (the process of obtaining the required side slip velocity change rate correction amount Vgdot_y_cmpn according to Accy_err and γdot_err) is the first. This is the same as the embodiment.

  On the other hand, in the present embodiment, the vehicle motion estimator 24d obtains a side slip speed change rate necessary correction amount Vgdot_y_cmpn as a side slip speed correction operation amount Vgy_cmpn as a value obtained by passing through a filter 24d25 having a low cut characteristic. The processing is different from that of the first embodiment. In the present embodiment, the filter 24d5 is a low-cut filter (first-order low-cut filter having a time constant T5) whose transfer function is expressed by T5 * S / (1 + T5 * S). The vehicle motion estimator 24d adds a value obtained by adding the skid speed correction manipulated variable Vgy_cmpn to the vehicle center-of-gravity skid speed model estimated value Vgy_predict (current value) in the addition calculator 24d24, as in the first embodiment. The vehicle center-of-gravity skid speed estimated value Vgy_estm (current value) is determined.

  Here, as described in the description of the first embodiment, the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm corresponds to the error (= Vgdot_y_act−Vgdot_y_estm) with respect to the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act. The value obtained by passing the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut (or the vehicle center-of-gravity lateral acceleration deviation Accy_err) through the low-cut filter and the integrator is basically the actual value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict. It is considered that the vehicle gravity center side slip velocity Vgy_act converges to an error (= Vgy_act−Vgy_predict) or a value close thereto.

  On the other hand, in the present embodiment, in order to calculate the current value of the vehicle center of gravity skid speed model estimated value Vgy_predict by the above equation 1-19a, the previous value Vgy_estm_p of the vehicle center of gravity skid speed model estimated value is added to the previous value of the skid speed correction manipulated variable. Since the previous value Vgy_estm_p of the vehicle center-of-gravity skid speed estimated value is used as a value obtained by adding Vgy_cmpn_p, Vgy_cmpn is integrated in the calculation process of the vehicle center-of-gravity skid speed model estimated value Vgy_predict.

  Therefore, the process of calculating the current value of the vehicle center-of-gravity skid speed model estimated value Vgy_predict by the expression 1-19a substantially includes the process of integrating Accy_err_lowcut (or Accy_err).

  Therefore, in the present embodiment, the vehicle motion estimation unit 24d matches the Accy_err_lowcut in a situation where there is a high possibility that a change in the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut has occurred due to a change in the actual skidding motion of the vehicle 1. A value obtained by passing the side slip speed change rate necessary correction amount Vgdot_y_cmpn determined through the low cut filter 24d25 is determined as a side slip speed correction operation amount Vgy_cmpn. Then, the vehicle motion estimation unit 24d determines a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict using this Vgy_cmpn as the vehicle center-of-gravity skid speed estimated value Vgy_estm.

  The present embodiment is the same as the first embodiment except for the matters described above.

  Here, a supplementary description will be given of the correspondence between the present embodiment and the present invention. In the present embodiment, as in the first embodiment, the position of the center of gravity of the vehicle corresponds to the predetermined position of the vehicle in the present invention.

  Further, in the present embodiment, as in the first embodiment, the processing of the vehicle model calculation means 24 (the processing in S102 to S116 in FIG. 4 except for the processing in FIG. 9 executed in the processing in S114). Thus, the vehicle model calculation means in the present invention is realized. In this case, what corresponds to the friction characteristic model, the vehicle lateral force model value, the observed value of the predetermined type of observation target quantity, and the skid motion state quantity model value in the present invention is the same as in the first embodiment. However, in the present embodiment, the vehicle model according to the present invention is different from the expressions 1-2, 1-13a, and 1-19 in the arithmetic processes of the expressions 1-1 to 1-24 in the first embodiment. This is realized by arithmetic processing replaced with Formulas 1-2a, 1-13aa, and 1-19a. Further, in the present embodiment, in order to calculate a new value (current value) of the vehicle center-of-gravity skid speed model estimated value Vgy_predict corresponding to the skid motion state quantity model value in the present invention, the estimation of the skid motion state quantity in the present invention is performed. The previous value (past calculated value) Vgy_estm_p of the vehicle center-of-gravity skid speed estimated value Vgy_estm corresponding to the value is used.

  Similarly to the first embodiment, the lateral acceleration sensor 14 and the lateral acceleration detection means 22f of the observation target amount detection means 22 realize the predetermined position actual lateral acceleration detection means in the present invention. Similarly to the first embodiment, the yaw rate sensor 13 and the yaw angular acceleration detection means 22d of the observation target amount detection means 22 implement the yaw angular acceleration detection means in the present invention.

  Further, in the present embodiment, similar to the first embodiment, the processing of FIG. 9 executed in the processing of S112 (processing of the resultant force calculation unit 24c) and the processing of S114 (processing of the vehicle motion estimation unit 24d) Thus, the lateral acceleration model value calculating means, the lateral acceleration deviation calculating means, the yaw angular acceleration model value calculating means, the yaw angular acceleration deviation calculating means, and the skid motion state quantity estimated value determining means in the present invention are realized.

  Further, in the processing of S114-5 as the skid motion state quantity estimated value determining means (processing in the block diagram of FIG. 14), the filters 24d10 and 24d11 function as the fifth filter and the sixth filter in the present invention, respectively. The vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut and the yaw angular acceleration deviation filtering value γdot_err_lowcut correspond to the fifth filtering value and the sixth filtering value in the present invention, respectively.

  Further, the correction basic value determining means in the present invention is realized by the processing in the broken line frame of the block diagram of FIG. 14, and the correction calculating means in the present invention is realized by the processing of the filter 24d25 and the addition calculating unit 24d24. In this case, the side slip speed change rate required correction amount Vgdot_y_cmpn corresponds to the basic value in the present invention, and the side slip speed correction operation amount Vgy_cmpn corresponds to the correction operation amount in the present invention. The filter 24d25 functions as the fourth filter in the present invention.

  Similarly to the first embodiment, the linear combination value SUM (= Accy_err_lowcut + α2 * γdot_err_lowcut) corresponds to the linear combination value in the present invention, and the addition calculation units 24d17 and 24d18 calculate the linear combination value SUM. Function as. In this case, the setting form of the weighting factors α1 and α2 in the linear combination value SUM is the same as that in the first embodiment.

  According to the embodiment described above, when calculating the vehicle center-of-gravity skid speed estimated value Vgy_estm, a change in the vehicle center-of-gravity side acceleration deviation filtering value Accy_err_lowcut occurs due to a change in the actual skid motion of the vehicle 1. In situations where there is a high probability (Accy_err_lowcut and α2 * γdot_err_lowcut have the same polarity), the side slip speed change rate required correction amount Vgdot_y_cmpn matched with Accy_err_lowcut is passed through the low cut filter 24d25, so that the side slip speed correction manipulated variable Vgy_cmpn is determined. Then, the vehicle center-of-gravity skid speed estimated value Vgy_estm (current value) as a new value of the state value of the skid motion of the vehicle 1 generated by the external force of the total road surface reaction force combined lateral force estimated value Fgy_total_estm on the vehicle model. Is determined as a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict calculated using the past calculated value (previous value) of the vehicle center-of-gravity skid speed estimated value Vgy_estm by Vgy_cmpn. As a result, the accuracy of the vehicle center-of-gravity skid speed estimated value Vgy_estm in the transitional period in a situation where the skid motion of the vehicle 1 changes due to a change in the actual road surface friction coefficient μ_act or the like is obtained, and the vehicle center-of-gravity skid speed model estimated value Vgy_predict Than can be raised.

  In addition, the situation where the change in the vehicle center-of-gravity lateral acceleration deviation filtering value Accy_err_lowcut is likely to have occurred due to the change in the actual road bank angle θbank_act (the situation where Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities) Then, as in the first embodiment, the side slip velocity change rate required correction amount Vgdot_y_cmpn has the same polarity as Accy_err_lowcut, and is closer to “0” than Accy_err_lowcut, or “0”. Therefore, the skid speed correction manipulated variable Vgy_cmpn in this case is determined to be a value closer to “0” or determined to “0” than the value obtained by passing Accy_err_lowcut through the low cut filter 24d25. For this reason, when Accy_err_lowcut changes due to the change in the actual road bank angle θbank_act, the correction of the vehicle center of gravity side slip velocity model estimated value Vgy_predict is suppressed, and an inappropriate vehicle center of gravity side slip velocity estimated value Vgy_estm is calculated. Can be prevented. As a result, the reliability and stability of the vehicle center-of-gravity skid speed estimated value Vgy_estm can be improved.

  In this embodiment, the vehicle center-of-gravity skid speed estimated value Vgy_estm obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict using Vgy_cmpn is calculated as the vehicle center-of-gravity skid speed model estimated value Vgy_predict (current value). ) Is used in the processing to calculate the frequency characteristic of the transfer function of the arithmetic processing system from the output of the lateral acceleration sensor 15 to the skid speed correction manipulated variable Vgy_cmpn, the actual vehicle center of gravity longitudinal speed Vgx_act (actual vehicle speed) and actual road surface friction Influenced by change in coefficient μ_act. However, since the low cut filters 24d10, 24d11, and 24d25 are provided in the present embodiment, the convergence of the estimated vehicle center-of-gravity skid speed Vgy_estm with respect to the change in the actual vehicle center-of-gravity skid speed Vgy_act even when the actual road surface friction coefficient μ_act changes. The time constant of can be prevented from becoming too long.

  Supplementally, this embodiment is an embodiment of the sixth invention, and Vgy_cmpn is obtained using Accy_err_lowcut and γdot_err_lowcut. However, if the vehicle center-of-gravity lateral acceleration detection value Accy_sens or the yaw angular acceleration detection value γdot_sens does not include a steady offset component or the offset component is sufficiently small, the filter 24d10 24d11 may be omitted, and Vgy_cmpn may be obtained in the same manner as described above using Accy_err and γdot_err instead of Accy_err_lowcut and γdot_err_lowcut. By doing in this way, embodiment of the said 5th invention will be constructed | assembled.

  In this embodiment, the filter 24d25 for inputting the side slip velocity change rate necessary correction amount Vgdot_y_cmpn is provided. However, the filter 24d25 may be omitted, and Vgdot_y_cmpn may be used as it is as the side slip velocity correction operation amount Vgy_cmpn. . In particular, when the vehicle center-of-gravity lateral acceleration detection value Accy_sens and the yaw angular acceleration detection value γdot_sens do not include a stationary offset component or the offset component is sufficiently small, the filter 24d10, Both 24d11 and filter 24d25 may be omitted.

  In the present embodiment, the filters 24d10 and 24d11 for inputting Accy_sens and yaw γdot_sens and the filter 24d25 for inputting Vgdot_y_cmpn are provided as filters having low cut characteristics, but the vehicle center-of-gravity lateral acceleration detection value Accy_sens and If the yaw angular acceleration detection value γdot_sens does not include a steady offset component or the offset component is sufficiently small, either one of the filters 24d10, 24d11 and the filter 24d25 or Both may be omitted. However, when a stationary offset component is included in Accy_sens and γdot_sens, in order to change the polarity of Accy_err_lowcut and γdot_err_lowcut symmetrically between the positive polarity side and the negative polarity side, Of the filters 24d10, 24d11 and the filter 24d25, the filter 24d25 is preferably omitted.

  Each of the filters 24d10, 24d11, and 24d25 may be a band-pass filter having a low-cut characteristic in addition to a high-cut characteristic.

  Also, the weight coefficients α1 and α2 in the linear combination value (= α1 * Accy_err_lowcut + α2 * γdot_err_lowcut) of Accy_err_lowcut and γdot_err_lowcut are “1” and Iz / (m * Lnsp, respectively, as in the case described in the first embodiment. ) May be set to a different value.

  Alternatively, Vgy_cmpn may be set to “0” whenever Accy_err_lowcut and α2 * γdot_err_lowcut have different polarities.

  Further, instead of the processing in the broken line frame in FIG. 14, the side slip velocity change rate necessary correction amount Vgdot_y_cmpn may be obtained by executing the processing shown in the flowchart in FIG.

  Further, the vehicle motion estimation unit 24d may calculate the vehicle center-of-gravity skid angle estimated value βg_estm as an estimated value of one state quantity of the skid motion of the vehicle 1 as in the case described with respect to the first embodiment. Good.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. Note that this embodiment differs from the first embodiment only in a part of the processing of the control device 20.

  In the present embodiment, as shown in the block diagram of FIG. 15, the control device 20 includes a road surface in addition to the observation target amount detection means 22, the vehicle model calculation means 24, and the μ estimation means 26 as the main functional means. Bank angle estimation means 28 for sequentially executing a process of estimating a bank angle θbank (bank angle θbank of the road surface on which the vehicle 1 is traveling) and a road surface gradient angle θslope (gradient angle θslope of the road surface on which the vehicle 1 is traveling) Gradient angle estimating means 30 for sequentially executing the process of estimating.

  In this case, the functions and processes of the observation target amount detection unit 22 and the μ estimation unit 26 are the same as those in the first embodiment.

  On the other hand, in the present embodiment, the vehicle model calculation means 24 is different from the first embodiment only in a part of the processing (more specifically, processing of the vehicle motion estimation unit 24d (processing of S114 in FIG. 4)). In the processing of the vehicle motion estimator 24d, the road surface bank angle estimated value θbank_estm, which is an estimated value of the actual road surface bank angle θbank_act obtained by the bank angle estimating means 28 as described later, and the slope angle estimating means 30 are obtained as described later. The estimated road surface slope angle θslope_estm, which is the estimated value of the actual road surface slope angle θslope_act, is used.

  More specifically, in the processing of the vehicle model calculation means 24 in the present embodiment, a vehicle motion model that considers the road surface bank angle θbank and the road surface slope angle θslope is used instead of the vehicle motion model on the premise that the road surface is a horizontal plane. Used. For this reason, in the present embodiment, as shown in the block diagram of FIG. 15, the vehicle model calculation unit 24 includes an observation target amount detection value (δf_sens (= δ1_sens = δ2_sens) generated by the observation target amount detection unit 22, Vw_i_sens (i = 1, 2, 3, 4), γ_sens, γdot_sens, Accx_sens, Accy_sens, Tq_i_sens (i = 1, 2, 3, 4)) and the road surface friction coefficient estimated value μ_estm calculated by the μ estimating means 26 Are input as the bank surface angle estimation value θbank_estm and the road surface slope angle estimation value θslope_estm calculated by the bank angle estimation unit 28 and the gradient angle estimation unit 30 as described later.

  And in this embodiment, the vehicle model calculating means 24 calculates a road surface reaction force estimated value and a vehicle motion state quantity estimated value using these input values. In this case, the road surface reaction force estimated value calculated by the vehicle model calculating means 24 is the same as that in the first embodiment. On the other hand, the vehicle motion state amount estimated value calculated by the vehicle model calculating means 24 is a sensor-sensitive longitudinal acceleration estimated value Accx_sensor_estm which is an estimated value of the longitudinal acceleration of the vehicle 1 to which the longitudinal acceleration sensor 14 is sensitive. And a sensor-sensitive estimated lateral acceleration value Accy_sensor_estm, which is an estimated value of the lateral acceleration of the vehicle 1 to which the lateral acceleration sensor 15 is sensitive.

  In the present embodiment, the bank angle estimating means 28 includes the sensor-sensitive lateral acceleration estimated value Accy_sensor_estm and the vehicle center-of-gravity lateral acceleration detected value Accy_sens (= sensor-sensitive lateral acceleration detected value) generated by the observation target amount detecting means 22. Accy_sensor_sens). Then, the bank angle estimating means 28 obtains the road surface bank angle estimated value θbank_estm using these input values.

  In the present embodiment, the gradient angle estimating means 30 includes the sensor-sensitive longitudinal acceleration estimated value Accx_sensor_estm and the vehicle center-of-gravity longitudinal acceleration detected value Accx_sens (= sensor-sensitive longitudinal acceleration detected value generated by the observation target amount detecting means 22). Accx_sensor_sens). Then, the slope angle estimation means 30 obtains a road surface slope angle estimated value θslope_estm using these input values.

  Hereinafter, the processes of the vehicle model calculation unit 24, the bank angle estimation unit 28, and the gradient angle estimation unit 30 in the present embodiment will be described in more detail.

  The processing of the vehicle model calculation means 24 in the present embodiment is different from the first embodiment only in the processing of the vehicle motion estimation unit 24d. Therefore, the processes other than S114 among the processes of S102 to S116 in FIG. 4 are the same as those in the first embodiment. In this case, the vehicle motion estimation unit 24d in the present embodiment replaces the equations 1-13 and 1-14 with, for example, the following equations 1-13b and 1-14b, respectively (expressions 1-13b and 1 -14b and a vehicle motion model represented by the above formula 1-15), a vehicle motion state quantity estimated value is calculated. In this embodiment, the vehicle motion state quantity estimated value calculated by the vehicle motion estimation unit 24d includes Vgx_estm, Vgx_predict, Vgy_estm, Vgy_predict, γ_estm, γ_predict, Accx_sensor_estm, and Accy_sensor_estm.

Fgx_total = m * (Vgdot_x−Vgy * γ−g * sin (θslope)) ...... Formula 1-13b
Fgy_total = m * (Vgdot_y + Vgx * γ + g * sin (θbank)) ...... Formula 1-14b

Expression 1-13b is an expression obtained by adding an influence of the road surface gradient angle θslope (gravitational acceleration component in the longitudinal direction of the vehicle 1 due to θslope) to Expression 1-13 in the first embodiment. In this case, the influence of the road surface bank angle θbank (the lateral acceleration component of the vehicle 1 caused by θbank) is added to the expression 1-14 in the first embodiment. “G” is a gravitational acceleration constant.

  Specifically, the vehicle motion estimation unit 24 calculates the vehicle motion state quantity estimated value as follows. Note that the calculation process of the yaw rate estimated value γ_estm in the vehicle motion state quantity estimated value is exactly the same as that in the first embodiment, and thus the description thereof is omitted.

  The vehicle motion estimation unit 24d uses the following expression 1-13c obtained from the expression 1-13b and the following expression 1-14c obtained from the expression 1-14b, instead of the expressions 1-13a and 1-14a. A vehicle center-of-gravity longitudinal speed change rate estimated value Vgdot_x_estm and a vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm are calculated.

Vgdot_x_estm = Fgx_total_estm / m + Vgy_predict_p * γ_estm_p
+ G * sin (θslope_estm_p) ...... Equation 1-13c
Vgdot_y_estm = Fy_total_estm / m-Vgx_estm_p * γ_estm_p
-G * sin (θbank_estm_p) ...... Formula 1-14c

In this case, Fx_total_estm and Fy_total_estm necessary for the calculations of Expressions 1-13c and 1-14c are the current values calculated by the resultant force calculation unit 24c in S112 of FIG. 4, and Vgx_estm_p, Vgy_predict_p, and γ_estm_p are calculated by the vehicle motion estimation unit 24d. The previous values θslope_estm_p and θbank_estm_p calculated in the previous calculation processing cycle are the previous values calculated by the gradient angle estimation unit 30 and the bank angle estimation unit 28, respectively, in the previous calculation processing cycle. The value m is a predetermined value set in advance. Note that the current value or the previous value of the yaw rate detection value γ_sens may be used instead of γ_estm_p. Further, the previous value or the current value of the wheel speed selection detection value Vw_i_sens_select may be used instead of Vgx_estm_p.

  Then, the vehicle motion estimation unit 24d obtains the vehicle center-of-gravity longitudinal speed model estimated value Vgx_predict and the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm by using the Vgdot_x_estm obtained as described above, in the same manner as in the first embodiment. That is, Vgx_estm is obtained by executing the arithmetic processing of the above formulas 1-18, 1-22, and 1-23. Note that the vehicle center-of-gravity longitudinal speed model estimated value Vgx_predict and the vehicle center-of-gravity longitudinal speed estimated value Vgx_estm may match the wheel speed selection detection value Vw_i_sens_select.

  Further, the vehicle motion estimation unit 24d obtains the vehicle center-of-gravity skid speed model estimated value Vgy_predict by using the Vgdot_y_estm obtained as described above by the same method as in the first embodiment. That is, Vgy_predict is obtained by the above equation 1-19 (by integration of Vgdot_y_estm).

  Further, in the present embodiment, the vehicle motion estimation unit 24d includes a sensor-sensitive longitudinal acceleration estimated value Accx_sensor_estm, which is an estimated value of acceleration to which the longitudinal acceleration sensor 14 is sensitive, and a sensor that is an estimated value of acceleration to which the lateral acceleration sensor 15 is sensitive. Sensitive lateral acceleration estimated values Accy_sensor_estm are calculated by the following equations 1-51a and 1-52a, respectively. That is, the vehicle motion estimation unit 24d divides the road surface reaction force combined longitudinal force estimated value Fgx_total_estm (current value) and the road surface reaction force combined lateral force estimated value Fgy_total_estm (current value) calculated in S112 by the vehicle mass m, respectively. As a result, Accx_sensor_estm and Accy_sensor_estm are calculated.

Accx_sensor_estm = Fgx_total_estm / m ...... Formula 1-51a
Accy_sensor_estm = Fgy_total_estm / m ...... Formula 1-52a

A value obtained by subtracting the second term and the third term on the right side from the value on the left side of Equation 1-13c is calculated as Accx_sensor_estm, and the value on the right side is calculated from the value on the left side of Equation 1-14c. A value obtained by subtracting the second term and the third term may be calculated as Accy_sensor_estm. That is, Accx_sensor_estm and Accy_sensor_estm may be calculated by the following expressions 1-51b and 1-52b, respectively.

Accx_sensor_estm = Vgdot_x_estm−Vgy_predict_p * γ_estm_p
-G * sin (θslope_estm_p) ...... Formula 1-51b
Accy_sensor_estm = Vgdot_y_estm + Vgx_estm_p * γ_estm_p
+ G * sin (θbank_estm_p) ...... Formula 1-52b

Furthermore, the vehicle motion estimation unit 24d determines a value obtained by correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict as the vehicle center-of-gravity skid speed estimated value Vgy_estm as described below. That is, the vehicle motion estimator 24d calculates the vehicle center-of-gravity lateral acceleration detected value Accy_sens obtained by the processing of S100 and the sensor-sensitive lateral acceleration estimated value Accy_sensor_estm calculated by the equation 1-52a or the equation 1-52b as described above. The deviation is calculated as a vehicle center-of-gravity lateral acceleration deviation Accy_err for correcting the vehicle center-of-gravity skid speed model estimated value Vgy_predict. That is, the vehicle center-of-gravity lateral acceleration deviation Accy_err for correcting Vgy_predict is calculated by the following equation 1-53.

Accy_err = Accy_sens−Accy_sensor_estm ...... Formula 1-53

Supplementally, since Accy_sens is the detected value of the actual sensor-sensitive lateral acceleration Accy_sensor_act (= Vgdot_y_act + Vgx_act * γ_act + g * sin (θbank_estm_p)), the second term on the right side of Equation 1-52b, that is, the turning motion of the vehicle 1 The estimated value of the lateral acceleration component of the center of gravity point of the vehicle 1 caused by the accompanying centrifugal force matches or substantially matches the actual value (= Vgx_act * γ_act) of the acceleration component, and the right side of Equation 1-52b In the state in which θbank_estm_p in the third term of the vehicle coincides or substantially coincides with the actual road bank angle θbank_act, the vehicle center-of-gravity lateral acceleration deviation Accy_err is an estimated value of the vehicle center-of-gravity skid speed change rate calculated by the equation 1-14c. This corresponds to an error (= Vgdot_y_act−Vgdot_y_estm) of Vgdot_y_estm (estimated value on the vehicle motion model) with respect to the actual vehicle center-of-gravity skid speed change rate Vgdot_y_act.

  Further, the vehicle motion estimation unit 24d calculates the yaw angular acceleration deviation γdot_err by executing the processes of S114-3 and S114-4 in FIG. 9 as in the first embodiment.

  Next, the vehicle motion estimation unit 24d corrects Vgy_predict according to Accy_err and γdot_err by the same method as in the first embodiment (by executing the same processing as that shown in the block diagram of FIG. 10). Is determined as a vehicle center-of-gravity skid speed estimated value Vgy_estm. Note that the processing of the flowchart of FIG. 13 may be executed instead of the processing within the broken line frame of FIG.

  The processing of the vehicle motion estimation unit 24d in the present embodiment is the same as that of the first embodiment except for the matters described above.

  Here, a supplementary description will be given of the correspondence between the present embodiment and the present invention. In the present embodiment, the vehicle model calculation means in the present invention is realized by the processing of the vehicle model calculation means 24 as in the first embodiment. However, in this case, in the present embodiment, the vehicle model according to the present invention is represented by the expressions 1-13, 1-14, 1-13a, of the arithmetic processes of the expressions 1-1 to 1-24 in the first embodiment. This is realized by arithmetic processing in which 1-14a is replaced with the formulas 1-13b, 1-14b, 1-13c, and 1-14c. Except for this, the correspondence between this embodiment and the present invention is the same as the correspondence between the first embodiment and the present invention.

  Next, the processing of the bank angle estimation means 28 and the processing of the gradient angle estimation means 30 in this embodiment are executed as shown in the flowchart of FIG. 16 and the flowchart of FIG.

  Here, the sensor-sensitive longitudinal acceleration estimated value Accx_sensor_estm obtained as described above by the vehicle model computing unit 24 is obtained by assuming that the previous value (latest value) θslope_estm_p of the road surface slope angle estimated value is accurate. It means acceleration estimated value. Similarly, Accy_sensor_estm obtained as described above by the vehicle model computing means 24 means a sensor-sensitive lateral acceleration estimated value obtained on the assumption that the previous value (latest value) θbank_estm_p of the road surface bank angle estimated value is accurate. . Therefore, the deviation between the vehicle center-of-gravity longitudinal acceleration detected value Accx_sens (= sensor-sensitive longitudinal acceleration detected value) based on the output of the longitudinal acceleration sensor 14 and the sensor-sensitive longitudinal acceleration estimated value Accx_sensor_estm is considered to be in accordance with the error of θslope_estm_p. It is done. Similarly, the deviation between the vehicle center-of-gravity lateral acceleration detected value Accy_sens (= sensor-sensitive lateral acceleration detected value) based on the output of the lateral acceleration sensor 15 and the sensor-sensitive lateral acceleration estimated value Accy_sensor_estm corresponds to the error of θbank_estm_p. Conceivable.

  Therefore, in the present embodiment, the bank angle estimating means 28 adjusts the deviation between the vehicle center-of-gravity lateral acceleration detected value Accy_sens and the sensor-sensitive lateral acceleration estimated value Accy_sensor_estm to converge to “0” by the feedback control law. Accordingly, a new road surface bank angle estimated value θbank_estm is obtained by updating the road surface bank angle estimated value θbank_estm. Similarly, the gradient angle estimating means 30 adjusts the road surface gradient according to the deviation so that the deviation between the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens and the sensor-sensitive longitudinal acceleration estimation value Accx_sensor_estm converges to “0” by the feedback control law. By updating the estimated angle value θslope_estm, a new estimated road slope angle value θslope_estm is obtained.

  Specifically, referring to FIG. 16, bank angle estimating means 28 first, in S120-1, vehicle center-of-gravity lateral acceleration detected value Accy_sens input from observation target amount detecting means 22 and vehicle model calculating means 24. The sensor-sensitive lateral acceleration deviation Accy_sensor_err (= Accy_sens−Accy_sensor_estm), which is a deviation from the sensor-sensitive estimated lateral acceleration value Accy_sensor_estm input from, is calculated.

  Next, in S120-2, the bank angle estimating means 28 calculates a bank angle increasing / decreasing manipulated variable Δθbank, which is an increasing / decreasing manipulated variable of the road surface bank angle estimated value θbank_estm, from the sensor-sensitive lateral acceleration deviation Accy_sensor_err by a feedback control law. In this case, in the present embodiment, a proportional law is used as the feedback control law, and Δθbank is calculated by multiplying Accy_sensor_err by a predetermined gain Kbank.

  Next, in S120-3, the bank angle estimating means 28 updates the previous value θbank_estm_p of the road bank angle estimated value with the bank angle increasing / decreasing manipulated variable Δθbank (adding the bank angle increasing / decreasing manipulated variable Δθbank to θbank_estm_p). ) To calculate a new estimated road bank angle value θbank_estm (current value).

  Therefore, in other words, the bank angle estimating means 28 in this embodiment determines a new road surface bank angle estimated value θbank_estm by the following equation 1-33.

θbank_estm = θbank_estm_p + Kbank * (Accy_sens−Accy_sensor_estm)
... Formula 1-33

Referring to FIG. 17, the gradient angle estimating means 30 is first inputted with the vehicle center-of-gravity longitudinal acceleration detection value Accx_sens inputted from the observation target amount detecting means 22 and the vehicle model calculating means 24 in S120-11. The sensor sensitive longitudinal acceleration deviation Accx_sensor_err (= Accx_sens−Accx_sensor_estm), which is a deviation from the estimated sensor sensitive longitudinal acceleration value Accx_sensor_estm, is calculated.

  Next, in S120-12, the gradient angle estimation means 30 calculates the gradient angle increase / decrease operation amount Δθslope, which is the increase / decrease operation amount of the road surface gradient angle estimated value θslope_estm, from the sensor-sensitive longitudinal acceleration deviation Accx_sensor_err by the feedback control law. In this case, in this embodiment, a proportional law is used as the feedback control law, and Δθslope is calculated by multiplying Accx_sensor_err by a predetermined gain Kslope.

  Next, in S120-13, the gradient angle estimating means 30 updates the previous value θslope_estm_p of the road surface gradient angle estimated value with the gradient angle increasing / decreasing manipulated variable Δθslope (adding the gradient angle increasing / decreasing manipulated variable Δθslope to θslope_estm_p). ) To calculate a new road surface slope angle estimated value θslope_estm (current value).

  Therefore, in other words, the gradient angle estimating means 30 in this embodiment determines a new road surface gradient angle estimated value θslope_estm by the following equation 1-34.

θslope_estm = θslope_estm_p + Kslope * (Accx_sens−Accx_sensor_estm)
... Formula 1-34

The above is the details of the present embodiment. In this embodiment, the same effect as that of the first embodiment can be obtained.

  In this embodiment, as in the first embodiment, the vehicle center-of-gravity skid speed estimated value Vgy_estm is not fed back to the calculation process of the vehicle center-of-gravity skid speed model estimated value Vgy_predict, but as in the second embodiment. Vgy_estm may be fed back to the calculation process of the vehicle center-of-gravity skid speed model estimated value Vgy_predict. In this case, instead of the formula 1-2 and the formula 1-19 in the first embodiment, the formula 1-2a and the formula 1-19a described in the second embodiment are used. In the embodiment, a formula obtained by replacing Vgy_predict_p on the right side of the formula 1-13c with the previous value Vgy_estm_p of the vehicle center-of-gravity skid speed estimated value may be used.

  In the first to third embodiments described above, the case where the vehicle center-of-gravity skid speed Vgy is estimated as the side skid motion state quantity of the vehicle has been described as an example. However, in addition to the vehicle center-of-gravity skid speed Vgy or Vgy Instead of this, the vehicle gravity center side slip angle βg may be estimated.

  In each of the embodiments described above, the position of the center of gravity of the vehicle 1 is used as the predetermined position of the vehicle in the present invention, but a position different from the center of gravity (for example, the front wheels 2-1 and 2-2). The center position on the axle, the center position on the axle of the rear wheels 2-3, 2-4, etc.) is used as the predetermined position of the vehicle in the present invention, and the skid speed and the skid angle at that position are used for the skid motion. You may make it estimate as a state quantity.

  Further, in each of the above embodiments, while estimating the vehicle motion state quantity such as the vehicle gravity center side slip velocity Vgy, the road surface friction coefficient μ is estimated by the above-described method. You may make it estimate by the arbitrary well-known methods different from embodiment.

  In each of the above embodiments, the example in which the road surface friction coefficient μ is estimated based on the road surface reaction force estimated using the vehicle center-of-gravity skid speed model estimated value Vgy_predict has been described. However, the road surface friction coefficient μ is estimated. In the processing, the road surface friction coefficient μ may be estimated based on the road surface reaction force estimated using the vehicle center-of-gravity skid speed estimated value Vgy_estm. Alternatively, the road surface friction coefficient μ may be estimated by an estimation process that does not require an estimated value of the skid motion state quantity of the vehicle 1, or the road surface friction coefficient μ estimation process may be omitted.

  For example, when the estimated value of the skid motion state quantity of the vehicle 1 is used for the estimation process of the road surface friction coefficient μ and the control process of the skid motion state quantity of the vehicle 1, the estimation of the skid motion state quantity to be used for each is used. The value may not be the same estimated value. For example, the vehicle center-of-gravity skid speed estimated value Vgy_estm may be used in one of the estimation process and the control process, and the vehicle center-of-gravity skid speed model estimated value Vgy_predict may be used in the other process.

  Further, in each of the above embodiments, the driving / braking force estimated value Fsubx_i_estm and the lateral force estimated value Fsuby_i_estm of each wheel 2-i are obtained as road surface reaction forces acting on the wheels 2-i, and these estimated values are used as the basis. In addition, although the side slip motion state quantity of the vehicle 1 is estimated, the side slip motion of the vehicle 1 is highly dependent on the side force of the side force and driving / braking force of each wheel 2-i. Therefore, when the side-slip motion state quantity of the vehicle 1 is estimated by the vehicle motion estimation unit 24d, the center of gravity of the vehicle 1 is determined by the resultant force of the estimated lateral force Fsuby_i_estm of the wheels 2-i (i = 1, 2, 3, 4). Only the lateral translational force acting on the point may be regarded as the entire lateral external force (translational force) acting on the center of gravity of the vehicle 1, and the skid motion state quantity of the vehicle 1 may be estimated. For example, the value of the lateral translation force acting on the center of gravity of the vehicle 1 due to the resultant force of the lateral force estimated value Fsuby_i_estm of the wheel 2-i (i = 1, 2, 3, 4) is calculated as the total road surface reaction force combined lateral force. By obtaining the estimated value Fgy_total_estm and performing the calculation of the equation 1-14a using this Fgy_total_estm, the vehicle center-of-gravity skid speed change rate estimated value Vgdot_y_estm is obtained and the Vgdot_y_estm is integrated to obtain the vehicle center-of-gravity skid speed model estimated value Vgy_predict May be requested.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2-1, 2-2, 2-3, 2-4 ... Wheel, 13 ... Yaw rate sensor (yaw angular acceleration detection means), 22d ... Yaw angular acceleration detection means, 15 ... Lateral acceleration sensor (predetermined position) Actual lateral acceleration detecting means), 22f... Lateral acceleration detecting means (predetermined position actual lateral acceleration detecting means), 24 (S102 to S116) ... Vehicle model calculating means, S112, S114-1 ... Lateral acceleration model value calculating means, S114- 2 ... Lateral acceleration deviation calculating means, S112, S114-3 ... Yaw angular acceleration model value calculating means, S114-4 ... Yaw angular acceleration deviation calculating means, S114-5 ... Side slip movement state quantity estimated value determining means, 24d10 ... Filter ( 2nd filter, 5th filter), 24d11 ... filter (3rd filter, 6th filter), 24d22 ... filter (1st filter, correction arithmetic means), 24d23 ... gain Calculation unit (gain multiplication means, correction calculation means), 24d25 ... filter (fourth filter, correction calculation means), 24d12 to 24d21, S114-11 to S114-19 ... correction basic value determination means, 24d24 ... addition calculation section (correction) Arithmetic means), 24d17, 24d18, S114-11 ... linear combination value calculation means.

Claims (6)

A skid angle or a skid speed at a predetermined position of a vehicle is set as a skid motion state quantity to be estimated, and a device that sequentially estimates a value of the skid motion state quantity,
Including a friction characteristic model representing a relationship between slippage between a vehicle wheel and a road surface and a road surface reaction force acting on the wheel from the road surface, and using a vehicle model expressing the dynamics of the vehicle, at least on the vehicle model By performing an arithmetic processing of the vehicle model while inputting an observation value of a predetermined type of observation target amount related to the actual vehicle behavior necessary for specifying the slip of the vehicle wheel at the vehicle model, A road surface reaction force model value that is a value of a road surface reaction force including at least a lateral force out of road surface reaction forces acting on each wheel of the vehicle on the vehicle model from the road surface is obtained, and a resultant force of the road surface reaction force model value Vehicle model computing means for obtaining a skid motion state quantity model value that is a value of the skid motion state quantity generated in a vehicle on the vehicle model;
A predetermined position actual lateral that includes at least a lateral acceleration sensor that is sensitive to the actual lateral acceleration of the vehicle and that generates an output in accordance with the predetermined actual lateral acceleration that is the actual lateral acceleration of the predetermined position of the vehicle; Acceleration detection means;
Using the road surface reaction force model value, a predetermined position lateral acceleration model value, which is a value of a lateral acceleration of the vehicle, in which a resultant force of the road surface reaction force model value is generated at the predetermined position in the vehicle on the vehicle model. A lateral acceleration model value calculation means to be obtained;
Lateral acceleration deviation calculating means for obtaining a lateral acceleration deviation which is a deviation between a detected value of the predetermined position actual lateral acceleration indicated by the output of the predetermined position actual lateral acceleration detecting means and the predetermined position lateral acceleration model value;
A yaw angular acceleration detecting means for generating an output corresponding to an angular acceleration around a predetermined yaw axis of an actual vehicle;
Yaw angular acceleration for obtaining a yaw angular acceleration model value, which is a value of angular acceleration generated around the predetermined yaw axis in the vehicle on the vehicle model, by using the road surface reaction force model value. Model value calculation means;
A yaw acceleration deviation calculating means for obtaining a yaw angular acceleration deviation which is a deviation between the detected value of the angular acceleration indicated by the output of the yaw angular acceleration detecting means and the yaw angular acceleration model value;
Side slip movement state quantity estimated value determination is performed by determining a value obtained by correcting the side slip movement state quantity model value according to the side acceleration deviation and the yaw angular acceleration deviation as an estimated value of the actual side slip movement state quantity of the vehicle. And a vehicle skid motion state quantity estimating device. The vehicle skid motion state quantity estimation device according to claim 1,
The vehicle side-slip motion state quantity estimating device, wherein the predetermined position of the vehicle is a position of a center of gravity of the vehicle. The vehicle skid motion state quantity estimation device according to claim 1 or 2,
The vehicle model calculation means includes means for sequentially obtaining a new value of the skid motion state quantity model value using the road reaction force model value and a past calculated value of the skid motion state quantity model value,
The skid motion state quantity estimated value determining means includes:
A linear combination value (α1 * A + α2 * B) obtained by linearly combining the lateral acceleration deviation (A) and the yaw angular acceleration deviation (B) using two weighting factors (α1) and (α2), respectively. Linear combination value calculation means for obtaining
Correction basic value determining means for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value;
A value obtained by passing the basic value through a first filter having a high-cut characteristic, or a value obtained by passing the basic value through the first filter and a gain multiplication unit that multiplies an input value by a gain of a predetermined value is used as the correction operation amount. Correction calculating means for determining a value obtained by adding the correction operation amount to the side-slip motion state amount model value as an estimated value of the actual side-slip motion state amount of the vehicle,
The two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are such that the leftward direction toward the front of the vehicle is a positive direction of the lateral acceleration of the vehicle, and the vehicle is When the counterclockwise direction when viewed from above is defined as the positive direction of angular acceleration around the yaw axis of the vehicle, the actual vehicle's neutral steer point (hereinafter referred to as NSP) is behind the center of gravity of the vehicle. The two weighting factors (α1), (α2) are of the same polarity when they are present on the side, and the two weighting factors (α1), (α2) are present when the NSP is ahead of the center of gravity of the vehicle. α2) are set to have different polarities,
When the linear combination value (α1 * A + α2 * B) has a polarity different from the term (α1 * A) including the lateral acceleration deviation (A) in the linear combination value, the correction basic value determination means When “0” is determined as the basic value and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the lateral acceleration deviation (A), A vehicle side-slip motion state quantity estimating device that determines a value closer to “0” of a combined value (α1 * A + α2 * B) and the lateral acceleration deviation (A) as the basic value. The vehicle skid motion state quantity estimation device according to claim 1 or 2,
The vehicle model calculation means includes means for sequentially obtaining a new value of the skid motion state quantity model value using the road reaction force model value and a past calculated value of the skid motion state quantity model value,
The skid motion state quantity estimated value determining means includes:
A second filtering value (A) obtained by passing the lateral acceleration deviation through a second filter having a low cut characteristic, and a third filtering value obtained by passing the yaw angular acceleration deviation through a third filter having a low cut characteristic. Linear combination value calculating means for obtaining a linear combination value (α1 * A + α2 * B) obtained by linearly combining (B) using two weighting factors (α1) and (α2) applied to each of the (B),
Correction basic value determining means for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value;
A value obtained by passing the basic value through a first filter having a high-cut characteristic, or a value obtained by passing the basic value through the first filter and a gain multiplication unit that multiplies an input value by a gain of a predetermined value is used as the correction operation amount. Correction calculating means for determining a value obtained by adding the correction operation amount to the side-slip motion state amount model value as an estimated value of the actual side-slip motion state amount of the vehicle,
The two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are such that the leftward direction toward the front of the vehicle is a positive direction of the lateral acceleration of the vehicle, and the vehicle is When the counterclockwise direction when viewed from above is defined as the positive direction of angular acceleration around the yaw axis of the vehicle, the actual vehicle's neutral steer point (hereinafter referred to as NSP) is behind the center of gravity of the vehicle. The two weighting factors (α1), (α2) are of the same polarity when they are present on the side, and the two weighting factors (α1), (α2) are present when the NSP is ahead of the center of gravity of the vehicle. α2) are set to have different polarities,
When the linear combination value (α1 * A + α2 * B) has a different polarity from the term (α1 * A) including the second filtering value (A) in the linear combination value, the correction basic value determination unit , “0” is determined as the basic value, and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the second filtering value (A), A vehicle side-slip motion state quantity estimation device that determines a value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) as the basic value. . The vehicle skid motion state quantity estimation device according to claim 1 or 2,
The vehicle model calculation means has means for sequentially obtaining a new value of the side-slip motion state quantity model value using the road surface reaction force model value and a past calculated value of the estimated value of the side-slip movement state quantity,
The skid motion state quantity estimated value determining means includes:
A linear combination value (α1 * A + α2 * B) obtained by linearly combining the lateral acceleration deviation (A) and the yaw angular acceleration deviation (B) using two weighting factors (α1) and (α2), respectively. Linear combination value calculation means for obtaining
Correction basic value determining means for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value;
The basic value or a value obtained by passing the basic value through a fourth filter having a low-cut characteristic is used as the correction operation amount, and a value obtained by adding the correction operation amount to the skid motion state amount model value is used as an actual vehicle. Correction calculating means for determining as an estimated value of the skid motion state quantity,
The two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are such that the leftward direction toward the front of the vehicle is a positive direction of the lateral acceleration of the vehicle, and the vehicle is When the counterclockwise direction when viewed from above is defined as the positive direction of angular acceleration around the yaw axis of the vehicle, the actual vehicle's neutral steer point (hereinafter referred to as NSP) is behind the center of gravity of the vehicle. The two weighting factors (α1), (α2) are of the same polarity when they are present on the side, and the two weighting factors (α1), (α2) are present when the NSP is ahead of the center of gravity of the vehicle. α2) are set to have different polarities,
When the linear combination value (α1 * A + α2 * B) has a polarity different from the term (α1 * A) including the lateral acceleration deviation (A) in the linear combination value, the correction basic value determination means When “0” is determined as the basic value and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the lateral acceleration deviation (A), A vehicle side-slip motion state quantity estimating device that determines a value closer to “0” of a combined value (α1 * A + α2 * B) and the lateral acceleration deviation (A) as the basic value. The vehicle skid motion state quantity estimation device according to claim 1 or 2,
The vehicle model calculation means has means for sequentially obtaining a new value of the side-slip motion state quantity model value using the road surface reaction force model value and a past calculated value of the estimated value of the side-slip movement state quantity,
The skid motion state quantity estimated value determining means includes:
A fifth filtering value (A) obtained by passing the lateral acceleration deviation through a fifth filter having a low cut characteristic, and a sixth filtering value obtained by passing the yaw angular acceleration deviation through a sixth filter having a low cut characteristic. Linear combination value calculating means for obtaining a linear combination value (α1 * A + α2 * B) obtained by linearly combining (B) using two weighting factors (α1) and (α2) applied to each of the (B),
Correction basic value determining means for determining a basic value of a correction operation amount for correcting the skid motion state quantity model value;
The basic value or a value obtained by passing the basic value through a fourth filter having a low-cut characteristic is used as the correction operation amount, and a value obtained by adding the correction operation amount to the skid motion state amount model value is used as an actual vehicle. Correction calculating means for determining as an estimated value of the skid motion state quantity,
The two weighting factors (α1) and (α2) in the linear combination value (α1 * A + α2 * B) are such that the leftward direction toward the front of the vehicle is a positive direction of the lateral acceleration of the vehicle, and the vehicle is When the counterclockwise direction when viewed from above is defined as the positive direction of angular acceleration around the yaw axis of the vehicle, the actual vehicle's neutral steer point (hereinafter referred to as NSP) is behind the center of gravity of the vehicle. The two weighting factors (α1), (α2) are of the same polarity when they are present on the side, and the two weighting factors (α1), (α2) are present when the NSP is ahead of the center of gravity of the vehicle. α2) are set to have different polarities,
When the linear combination value (α1 * A + α2 * B) has a different polarity from the term (α1 * A) including the fifth filtering value (A) in the linear combination value, the correction basic value determination means , “0” is determined as the basic value, and the linear combination value (α1 * A + α2 * B) has the same polarity as the term (α1 * A) including the fifth filtering value (A), A vehicle side-slip motion state quantity estimation device that determines a value closer to “0” of the linear combination value (α1 * A + α2 * B) and the lateral acceleration deviation (A) as the basic value. .

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