JP5272799B2 - Vehicle suspension system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the practicality of a suspension system having an electromagnetic actuator. <P>SOLUTION: This vehicular suspension system can selectively execute (A) first control (S7) by which actuator power generated by an actuator is controlled on the basis of a predetermined rule and (B) second control (S10) for generating the actuator power as a braking force having a value depending on an electromotive force generated at a motor by mutually short-circuiting energized terminals at each of phases of the motor. In the case that the second control is changed to the first control, a target actuator force F* is decided by weighing actuator forces and summing them (S16, S17) on the basis of the actuator force F<SB>A</SB>which should be generated by the actuator when the first control is executed, and the actuator force F<SB>S</SB>which may be generated when the second control is executed, and control-changeover-time control for controlling the actuator forces can be executed so that the actuator forces reach the decided target actuator force F". <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vehicle suspension system including an electromagnetic actuator that generates a force in a direction of approaching and separating from an unsprung portion and an unsprung portion.

  In recent years, suspension systems for vehicles include an electromagnetic shock absorber that relies on the force of an electromagnetic motor to generate a force in the direction in which they move toward and away from the unsprung and unsprung parts. An electromagnetic suspension system has been studied. For example, there is a system described in the following patent document. This electromagnetic suspension system is expected as a high-performance system because of its advantage that vibration damping characteristics based on the so-called skyhook damper theory can be easily realized.

  In a suspension system equipped with an electromagnetic actuator, for example, when a failure occurs that prevents the electromagnetic motor of the actuator from being driven normally, appropriate control is not performed, and vehicle operability and ride comfort are reduced. There is a risk of worsening. In the system described in Patent Document 1 below, when one of a plurality of actuators provided corresponding to each wheel fails, the traveling state of the vehicle can be determined only by the other actuators that have not failed. It is configured to perform a stabilizing control. In addition, the system described in Patent Document 2 below includes a terminal-to-terminal conduction state in which the current-carrying terminals of the respective phases of the electromagnetic motor included in the actuator are electrically connected to each other, and a power supply without electrically connecting the current-carrying terminals to each other. A conduction / non-conduction switcher that switches between non-terminal states that allow current flow to the electromagnetic motor is provided. When a failure occurs in the system, the conduction / non-conduction switch switches each phase of the electromagnetic motor. By connecting (short-circuiting) between the current-carrying terminals, a damping force is generated with respect to the relative movement between the spring top and the spring bottom.

JP 2005-162021 A JP 2003-223220 A

  For example, when the electromagnetic motor falls into a state where current cannot be supplied due to the charged state of the power supply, each of the actuators corresponding to all the wheels as in the system described in Patent Document 2 above. A suspension system has been studied in which a conduction state between terminals is realized with respect to an electromagnetic motor, and when such a situation is resolved, a normal control is restored. However, in such a system, there is a possibility that switching of control may be performed many times during traveling of the vehicle, and there is a problem that the riding comfort of the vehicle is deteriorated by the switching of control. It is considered that the practicality of a suspension system including an electromagnetic actuator can be improved by addressing this problem. This invention is made | formed in view of such a situation, and makes it a subject to improve the practicality of the suspension system provided with the electromagnetic actuator.

In order to solve the above-mentioned problems, the suspension system for a vehicle according to the present invention realizes a non-conductive state between terminals by (A) a conduction / non-conduction switch and the actuator force generated by the actuator to a predetermined rule. The actuator control is generated as a braking force having a magnitude based on the electromotive force generated in the electromagnetic motor by realizing the terminal-to-terminal conduction state by the first control based on (B) the conduction / non-conduction switch. The second control is configured to be selectively executable, and when switching from one of the first control and the second control to the other, a non-conduction state between terminals is realized by a conduction / non-conduction switch. The actuator force that should be generated when the first control is executed and the actuator generated when the second control is executed. Based on the actuator force, by summing each of the by weighting, to determine the target actuator force, to perform a control switching control for controlling the actuator force such that the determined target actuator force is configured, the control switching control, (i) from the first control when switching to the second control, over time, while reducing the weight of the first control when the actuator force, the second (Ii) When switching from the second control to the first control, the second control is performed while increasing the weight of the first control actuator force as time elapses. The target actuator force is determined by reducing the weight of the actuator force when the determined target actuator is determined As a, wherein the actuator is configured to control the actuator force to be generated.

  According to the suspension system of the present invention, when the two controls are switched, it is possible to reduce a sense of discomfort felt by the occupant when the control is switched by executing the control switching control. Can be prevented. Having such an advantage makes the suspension system of the present invention highly practical.

Aspects of the Invention

In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. In each of the following items, the combination of items (1) and (2) corresponds to claim 1, and each of items (3) to (5) corresponds to each of claims 2 to 4 . It corresponds to.

(1) an actuator having an electromagnetic motor and generating an actuator force which is a force in a direction in which the spring upper part and the spring lower part approach and separate from each other based on the force generated by the electromagnetic motor;
Allowing the current flow from the power supply to the electromagnetic motor without conducting the mutual conduction between the current-carrying terminals and the current-carrying state between the current-carrying terminals of each phase of the electromagnetic motor of the actuator. A conduction / non-conduction switching device for switching between the terminal non-conduction states;
A control device for controlling the actuator and the conduction / non-conduction switch, wherein (A) the conduction / non-conduction switch realizes a non-terminal state between the terminals and determines the actuator force generated by the actuator. A first control that is controlled on the basis of the given rule; and (B) the conduction between terminals is realized by the conduction / non-conduction switching device, whereby the actuator force generated by the actuator is converted into an electromotive force generated in the electromagnetic motor. A suspension system for a vehicle, comprising: a control device that selectively executes second control to be generated as a braking force having a magnitude depending on the vehicle;
The control device is
When switching from one of the first control and the second control to the other of the first control and the second control, a non-conduction state between terminals is realized by the conduction / non-conduction switch, and the first control When the control is executed, the first control time actuator force that is the actuator force to be generated by the actuator and when the second control is executed the second control time is the actuator force that the actuator generates. Based on the actuator force, each of them is weighted and added to determine a target actuator force that is an actuator force to be generated by the actuator, and the actuator is set to the determined target actuator force. Execute the control at the time of control switching that controls the actuator force generated by Suspension system for a vehicle according to claim.

  When the control is instantaneously switched between the first control and the second control, the occupant feels uncomfortable when the control itself is suddenly switched, or the actuator force changes suddenly when the control is switched. This makes the passenger feel uncomfortable. On the other hand, according to the suspension system described in this section, when the control is switched between the first control and the second control, the control switching control is executed for a set time, for example. Thus, it is possible to gradually switch the control from one of the two controls to the other of them. As a result, it is possible to reduce the sense of discomfort felt by the occupant when the control is switched and the sense of discomfort felt by the occupant due to a sudden change in the actuator force when the control is switched, thereby suppressing deterioration in the riding comfort of the vehicle. It is possible.

  The “actuator force” described in this section is the force for the approaching / separating operation between the sprung portion and the unsprung portion, but this force means not only the resistance force for the approaching / separating operation but also the driving force for the approaching / separating operation. To do. Therefore, the “predetermined rule” in the “first control” executed by the “control device” according to the aspect of this section is, for example, a rule relating to control for the purpose of vibration damping for causing the actuator to function as a shock absorber. be able to. Specifically, for example, there are rules for executing control based on the speed of motion of the sprung portion, that is, control based on the so-called skyhook damper theory. In addition to the vibration damping control, roll suppression control for suppressing the roll of the vehicle body caused by turning of the vehicle, pitch suppression control for suppressing the pitch of the vehicle body caused by acceleration / deceleration of the vehicle, and a spring top It may be a rule that executes control for adjusting the distance between the spring and the unsprung portion, that is, so-called vehicle height adjustment control or the like in parallel.

  On the other hand, the “second control” does not perform any special control on the actuator, but only realizes the inter-terminal conduction state for the electromagnetic motor, and the actuator generates the actuator force exclusively as a braking force. become. Therefore, the “control switching control” in the aspect of this section estimates the force generated by the actuator when the second control is assumed to be executed, and similarly to the estimated force and the first control. The target actuator force can be determined based on the determined actuator force. More specifically, the method for estimating the braking force that the actuator will generate in the second control is, for example, that the magnitude of the electromotive force generated in the electromagnetic motor is proportional to the operating speed of the electromagnetic motor. By detecting an index related to the operating speed of the electromagnetic motor based on the fact that there is a specific relationship between the operating speed of the electromagnetic motor and the output obtained when the current-carrying terminals of each phase of the motor are conducted. It is possible to estimate the output of the electromagnetic motor, that is, the actuator force.

  For example, when the suspension system includes a drive circuit, the “conduction / non-conduction switch” described in this section can be configured to include the drive circuit. In this case, when the system is not a failure of the drive circuit, the control device controls the drive circuit to realize the terminal-to-terminal conduction state, and the drive circuit functions as a conduction / non-conduction switch. It can be. In addition, the “conduction / non-conduction switching device” may be provided separately from the drive circuit, and may be configured to switch between the inter-terminal conduction state and the inter-terminal non-conduction state. In this case, for example, it is possible to have a structure that switches between a terminal conduction state and a terminal non-conduction state by switching ON / OFF, that is, a switch, a relay, or the like. By the way, the conduction / non-conduction switching device may be one that conducts by making some resistance exist between the energization terminals of each phase of the electromagnetic motor, or it conducts by making a short circuit between the energization terminals. There may be.

  As the “actuator” in the aspect of this section, as described above, it is possible to employ one that can generate not only a resistance force but also a propulsive force with respect to the approaching / separating operation between the spring upper portion and the spring lower portion. For example, the “actuator” in the aspect of this section is the relative movement between the sprung unit connected to the sprung portion and the sprung unit connected to the sprung portion and moving toward and away from the sprung portion and the sprung portion. An unsprung-side unit capable of generating a force for relative movement between the unsprung-side unit and the unsprung-side unit based on the force of the electromagnetic motor, specifically speaking, It is possible to provide an electromagnetic shock absorber that can be expanded and contracted and generates a force for the expansion and contraction. In addition, an elastic body having one end connected to one of the spring upper part and the spring lower part is provided, and the actuator is disposed between the other end of the elastic body and the other of the spring upper part and the spring lower part, The amount of deformation of the elastic body is changed according to its own operating position by applying the force generated by itself depending on the motor force to the elastic body. It is also possible to make it a component of a so-called left and right independent type stabilizer device that generates a force in the direction in which they approach and separate.

(2) The control switching control is
(i) When switching from the first control to the second control, the weight of the actuator force during the second control is increased over time while the weight of the actuator force during the second control is decreased, ii) When switching from the second control to the first control, the weight of the actuator force during the second control is decreased with the passage of time, while the weight of the actuator force during the second control is decreased, The vehicle suspension system according to item (1), configured to determine a target actuator force and to control an actuator force generated by the actuator so as to be the determined target actuator force.

  The mode described in this section is a mode for embodying the weighting method. According to the mode of this section, switching is performed while reducing the force generated by the actuator in the control before switching between the two controls. The two controls are gradually switched so as to increase the force generated by the actuator in the subsequent control. In addition, the aspect of this term may be an aspect in which the weighting is continuously changed, or an aspect in which the weighting is changed step by step.

(3) The controller is
The control switching control is not executed when switching from the first control to the second control, but is executed only when switching from the second control to the first control (1) or (2) The vehicle suspension system described in 1.

  The mode described in this section is a particularly effective mode when the first control is the normal control and the second control is the fail control. Specifically, in the aspect of this section, when switching from the first control to the second control, the control switching control is not executed, and the second control, which is the control at the time of failure, is immediately performed. Can be switched. On the other hand, when switching from the second control to the first control, that is, when recovering from the temporary failure after executing the second control with a temporary failure as described later. It is possible to return to the normal control while reducing the uncomfortable feeling felt by the occupant as described above by the control switching control.

(4) The controller is
The vehicle suspension according to any one of (1) to (3), wherein the first control is executed in a normal state, and the second control is executed under a situation where the unsprung portion is operated vigorously. system.

  It is predicted that the electromotive force of the motor will increase under the situation where the unsprung part is operated vigorously. In such a case, if the second control is executed, it is possible to prevent a large load from being applied to the power source or the like in the circuit. The situation where the unsprung part can be vigorously operated is temporary, for example, when driving on rough roads or passing through unevenness on the road surface. is there. For example, the acceleration or speed of the unsprung portion can be employed as the index representing the above-mentioned “under circumstances where the unsprung portion can be vigorously operated”. Incidentally, when switching between the two controls using the index, the control may be switched based on the index value at the present time, or the control may be switched based on the index value within a set time traced back from the present time. . More specifically, for example, when the index value at the current time is larger than the set value, the first control is switched to the second control, and when the index value within the set time is smaller than the set value, the second control to the second control. It can be set as the aspect which switches to 1 control.

(5) The control device
The vehicle suspension according to any one of items (1) to (4), wherein the first control is executed at a normal time, and the second control is executed under a situation where a remaining energy amount of a power source is smaller than a set value. system.

  When the power supplied from the power source as a whole vehicle increases, the remaining energy amount of the power source may be reduced. In particular, the actuator requires a relatively large amount of power, and a large amount of power supplied to the actuator is likely to cause a decrease in the amount of remaining energy of the power source. Therefore, if the remaining energy amount of the power source is less than the set value and the second control is executed, the power supplied to the actuator is reduced to 0 and the power source is charged by the charging device mounted on the vehicle. Will be. That is, it is temporary that the remaining energy amount of the power source is less than the set value, and the control switching control is effective. In addition, not only the remaining energy amount but also the ratio of the remaining energy amount based on the charge amount and the charge capacity, the discharge voltage of the power source, etc. are used as an index indicating the situation where the remaining energy amount of the power source is less than the set value. You can also

  In addition, when the aspect of this section is combined with the aspect in which the second control is executed in the situation where the unsprung part described above is operated vigorously, the situation where the unsprung part is operated vigorously. And when the remaining energy amount of the power source is less than the set value, the second control is executed. It is desirable to switch to the first control.

(6) The first control is
The vehicle suspension system according to any one of (1) to (5), wherein the actuator force generated by the actuator is at least generated as a vibration damping force for attenuating the vibration of the sprung portion. .

  The mode described in this section is a mode in which the first control is limited, and is a mode in which control for vibration damping, that is, control based on the so-called skyhook damper theory can be executed. In the first control of the aspect of this section, not only the state in which the braking force is generated, but in some cases, the electromagnetic motor receives electric power from the power source, and the force in the same direction as the relative motion between the spring upper part and the spring lower part, That is, it can be in a state of generating a propulsive force. In other words, the second control only generates a damping force having a magnitude that depends on the electromotive force generated in the electromagnetic motor, whereas the first control provides an excellent vibration damping effect. Therefore, when the control is switched between the first control and the second control, the passenger may feel a great sense of discomfort due to the difference in vibration damping effect. Is particularly effective. In addition to the control based on the skyhook damper theory, the first control can execute a control based on a pseudo groundhook damper theory that generates a damping force against the vibration of the unsprung part. Control to be executed may be adopted.

(7) The vehicle suspension system is
(a) a high potential side switching element provided between the high potential side terminal of the power source and the energization terminal of one phase of the electromagnetic motor; and (b) a low potential side terminal of the power source and one phase of the electromagnetic motor. The electromagnetic motor includes a plurality of pairs of switching elements each including a low-potential side switching element provided between the current-carrying terminals corresponding to the total number of the electromagnetic motors, and controls the operation of the switching elements. The vehicle suspension system according to any one of (1) to (6), further comprising a drive circuit that drives the electromagnetic motor while controlling a current flowing through the motor.

(8) The control device
By controlling the operation of the switching elements of the plurality of switching element pairs, the inter-terminal conduction state is realized to execute the second control, or the inter-terminal non-conduction state is realized and the electromagnetic motor flows. In the item (7), the drive circuit is configured to function as the conduction / non-conduction switch by performing the first control by controlling the actuator force generated by the actuator by controlling the current. The vehicle suspension system described.

  The modes described in the above two items are modes in which the suspension system includes a so-called inverter. The inverter may be of any structure that can control the operation of switching elements such as FETs provided for each phase according to the electrical angle of the electromagnetic motor, and can execute PWM (Pulse Width Modulation) control. It is desirable to adopt a simple structure. According to the inverter, the electromagnetic motor can be easily and accurately controlled. Therefore, in the first control and the control switching control, the energization current that is the amount of current flowing to the electromagnetic motor is adjusted by the drive circuit. Thus, the actuator force generated by the actuator can be controlled. Further, it is possible to realize the inter-terminal conduction state by simply setting the ON / OFF states of the switching elements of the plurality of switching element pairs as described below, that is, to execute the second control. Therefore, in order to execute the second control, it is not necessary to provide and control a conduction / non-conduction switch in addition to the drive circuit. Therefore, a system with a relatively simple configuration can be obtained. The aspect is an aspect configured as such.

1 is a schematic diagram showing the overall configuration of a vehicle suspension system that is an embodiment of the claimable invention. It is front sectional drawing which shows the spring absorber Assy shown in FIG. It is a circuit diagram of the drive circuit which drives the electromagnetic motor which the actuator shown in FIG. 2 has. It is a figure which shows the relationship between the rotational speed of the electromagnetic motor which the actuator shown in FIG. 2 has, and an energization current. It is a figure which shows the magnitude | size of the weighting coefficient (alpha) of the actuator force at the time of 1st control with respect to the actuator force at the time of 2nd control used in control at the time of control switching. It is a flowchart showing the actuator control program performed by the suspension electronic control unit shown in FIG. It is a flowchart which shows the standard actuator force determination subroutine which is a part of actuator control program of FIG.

  Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do. Moreover, it is also possible to constitute the modification of the following Example using the technical matter described in the description of each item of [Aspect of the Invention].

<Configuration of suspension system>
FIG. 1 schematically shows a vehicle suspension system 10 that is an embodiment of the claimable invention. The suspension system 10 includes four independent suspension type suspension devices corresponding to the front, rear, left and right wheels 12, each of which is a spring absorber in which a suspension spring and a shock absorber are integrated. Assy20. The wheel 12 and the spring absorber assembly 20 are generic names, and when it is necessary to clarify which of the four wheels corresponds, as shown in FIG. In some cases, FL, FR, RL, and RR are attached to the front wheel, the right front wheel, the left rear wheel, and the right rear wheel.

  As shown in FIG. 2, the spring absorber assembly 20 is provided between a suspension lower arm 22 that holds the wheel 12 and constitutes a part of the unsprung part, and a mount part 24 that is provided on the vehicle body and constitutes a part of the unsprung part. These are arranged so as to connect them. The spring absorber assembly 20 includes an electromagnetic actuator 30 and a coil spring 32 as a suspension spring, and these are integrated.

  The actuator 30 includes a screw rod 40 as a male screw portion in which a thread groove is formed, and a ball screw mechanism configured to include a nut 42 as a female screw portion that holds a bearing ball and is screwed with the screw rod 40; An electromagnetic motor 44 (hereinafter sometimes simply referred to as “motor 44”) as a power source and a casing 46 for housing the motor 44 are provided. The casing 46 rotatably holds the screw rod 40 and is connected to the mount portion 24 via an anti-vibration rubber 48 at the outer peripheral portion. The motor 44 has a hollow motor shaft 50, and a screw rod 40 is fixed to the motor shaft 50 at the upper end portion through the inside thereof. That is, the motor 44 applies a rotational force to the screw rod 40.

  The actuator 30 has a cylinder 64 that includes an outer tube 60 and an inner tube 62 that fits into the outer tube 60 and protrudes upward from the upper end portion thereof. The outer tube 60 is connected to the lower arm 22 via a mounting bush 66 provided at the lower end portion thereof, and the inner tube 62 is fixed to the casing 46 at the upper end portion with the threaded rod 40 inserted therethrough. . A nut support cylinder 68 is erected on the inner bottom portion of the inner tube 62, and the nut 42 is fixed to the inner end of the inner tube 62 in a state of being screwed with the screw rod 40.

  Further, the actuator 30 has a cover tube 70, and the cover tube 70 is connected to the lower surface side of the mount portion 24 through the anti-vibration rubber 72 at the upper end portion with the cylinder 64 inserted. ing. A flange 74 (which functions as an upper retainer) is formed at the upper end of the cover tube 70, and the flange 74 and an annular lower retainer 76 provided on the outer peripheral surface of the outer tube 60. Thus, the coil spring 32 as a suspension spring is supported in a sandwiched state.

  Due to the structure as described above, the actuator 30 includes the sprung unit on the spring unit 40 including the screw rod 40, the motor 44, the casing 46, the inner tube 62, the cover tube 70, etc., the nut 42, the inner tube. 60, the nut supporting cylinder 68 and the like, and the unsprung unit connected to the lower arm 22. The relative rotation is impossible, and the approaching and separating operation between the sprung portion and the sprung portion is performed. The structure is movable in the axial direction, in other words, can be expanded and contracted.

  In the actuator 30, when the sprung portion and the unsprung portion are moved toward and away from each other, the sprung unit and the unsprung unit can move relative to each other in the axial direction, that is, the screw rod 40 and the nut 42 are moved in the axial direction. The relative movement is enabled, and the screw rod 40 rotates relative to the nut 42 with the relative movement. Thereby, the motor shaft 50 also rotates. The motor 44 can apply a rotational torque to the screw rod 40, and the rotational torque can generate a resistance force in a direction that prevents the relative rotation between the screw rod 40 and the nut 42. Is possible. By making this resistance force act as a damping force for the relative movement between the unsprung unit and the unsprung unit, and thus a damping force for the approaching and separating operation of the unsprung portion and unsprung portion, the actuator 30 can be used as a so-called shock absorber. As a function. The actuator 30 is also capable of generating a propulsive force for the relative motion between the sprung portion and the unsprung portion, and executes control based on the so-called skyhook damper theory, pseudo groundhook theory, and the like. Is possible. Furthermore, the rotational torque of the motor 44 can maintain the distance between the spring upper part and the spring lower part at an arbitrary distance. The roll of the vehicle body when turning the vehicle, the pitch of the vehicle body when accelerating / decelerating the vehicle, etc. It is possible to effectively suppress, adjust the height of the vehicle, the so-called vehicle height, and the like.

  In the present suspension system 10, the actuator 30 is controlled by a suspension electronic control unit 140 (hereinafter also referred to as “ECU 140”) as a control device. The ECU 140 is mainly configured by a computer having a CPU, a ROM, a RAM, and the like. The ECU 140 is connected to four inverters [INV] 146 which are provided corresponding to the motors 44 included in the actuators 30 and function as drive circuits for the corresponding motors 44. The inverters 146 are connected to the battery [BAT] 150 via the converter [CONV] 148, and the motor 44 of each actuator 30 receives power from a power source including the converter 148 and the battery 150. Supplied.

  The vehicle includes an ignition switch [I / G] 160, a vehicle speed sensor [v] 162 for detecting a vehicle traveling speed (hereinafter sometimes referred to as “vehicle speed”), and a steering wheel operating angle. Operation angle sensor [δ] 168, longitudinal acceleration sensor [Gx] 170 for detecting the actual longitudinal acceleration that is actually generated in the vehicle body, lateral acceleration for detecting the actual lateral acceleration that is actually generated in the vehicle body Sensor [Gy] 172, four sprung vertical acceleration sensors [Gzs] 174 for detecting the vertical acceleration (vertical acceleration) of each mount 24 of the vehicle body corresponding to each wheel 12, and 4 for detecting the vertical acceleration of each wheel 12. Two unsprung vertical acceleration sensors [Gzg] 176, throttle sensor [Sr] 178 for detecting the throttle opening, and master cylinder pressure of the brake Brake pressure sensor [Br] 180 for detecting, and the charge amount sensor [E] 182 or the like for measuring residual electric energy of the battery 150 is provided, which are connected to ECU140 computer. The ECU 140 controls the operation of the actuator 30 based on signals from these switches and sensors. Incidentally, the character [] is a symbol used when the above-mentioned switch, sensor, etc. are shown in the drawing. In addition, the ROM included in the computer of the ECU 140 stores a program related to the control of the actuator 30, various data, and the like.

  As shown in FIG. 3, the motor 44 of each actuator 30 is a three-phase DC brushless motor in which coils are star-connected (Y-connected), and is controlled by the inverter 146 described above. The inverter 146 is a general one as shown in FIG. 3, and a switching element pair composed of a switching element on the high side (high potential side) and a switching element on the low side (low potential side) of a power source is connected to a motor. There are three pairs corresponding to the U phase, V phase, and W phase, which are the three phases of 44. That is, six switching elements HUS, HVS, HWS, LUS, LVS, and LWS are provided. In addition, the switching element control circuit 190 included in the inverter 146 includes a resolver [θ] 192 provided in the motor 44 for detecting the rotation angle of the motor 44 and an actual motor 44 provided in the inverter 146. Three energizing current sensors [I] 194 for measuring an actual energizing current that is a current flowing through each of the phases are connected. The switching element control circuit 190 determines the rotational position (electrical angle) of the motor 44 by the resolver 192, and opens and closes the switching element according to the motor rotational position. The inverter 146 drives the motor 44 by so-called sine wave drive, and the current flowing in each of the three phases of the motor 44 changes in a sine wave shape, and the phase difference differs by 120 ° in electrical angle. In addition, the switching element is controlled. The switching element is controlled by changing the ratio (duty ratio) between the pulse-on time and the pulse-off time by PWM (Pulse Width Modulation) control.

  The direction of the rotational torque generated by the motor 44 may be the same as the direction in which the motor 44 is actually rotating, or vice versa. When the direction of the rotational torque generated by the motor 44 and the rotational direction of the motor 44 are reversed, that is, when the actuator 30 is acting as a resistance force against the relative movement between the wheel and the vehicle body, The force generated by 44 does not necessarily depend on the power supplied from the power source. More specifically, when the motor 44 is rotated by an external force, an electromotive force is generated in the motor 44. When the motor 44 generates a motor force depending on the electromotive force, that is, the actuator 30 starts. In some cases, an actuator force depending on electric power is generated.

  FIG. 4 conceptually shows the relationship between the rotational speed ω of the motor 44 and the rotational torque generated by the motor 44 (the energization current of the motor 44). Region (a) in this figure is a region where the direction of rotational torque of motor 44 is the same as the direction of rotation, and region (b) and region (c) are the direction of rotational torque and direction of rotation of motor 44. This is the opposite area. The line that divides the region (b) and the region (c) is a characteristic line when the current-carrying terminals of each phase of the motor 44 are short-circuited, that is, the rotation speed of the motor 44 obtained when so-called short-circuit braking is performed. It is a short circuit characteristic line which shows the relationship between (omega) and rotational torque. The region (c) where the rotational torque generated by the motor 44 with respect to the rotational speed ω is smaller than the rotational torque on the short-circuit characteristic line is the region where the motor 44 generates rotational torque that becomes a resistance force depending on the electromotive force. Incidentally, the area (b) is an area in which the motor 44 receives a supply of electric power from the battery 150 and generates a torque that becomes a resistance force, that is, a so-called reverse braking area. The area (a) is an area in which the motor 44 receives electric power from the battery 150. This is a region that receives the supply of torque and generates a torque as a driving force.

  Note that the inverter 146 has a structure that can regenerate the power generated by the electromotive force in the battery 150. In other words, when the relationship between the rotational speed ω of the motor 44 and the rotational torque generated by the motor 44 is in the region (c), the generated power based on the electromotive force is regenerated. In the case where the rotational torque generated by the motor 44 and the rotational direction of the motor 44 are reversed, the PWM control of the switching element described above controls the current flowing through each coil of the motor 44 by the electromotive force. Therefore, the magnitude of the rotational torque generated by the motor 44 is changed by changing the duty ratio. That is, the inverter 146 adjusts the current flowing through the coil of the motor 44, that is, the energization current of the motor 44, regardless of whether the current is supplied from the power source or the generated current caused by the electromotive force. It is structured to control the motor force.

<Control of suspension system>
i) Standard control (first control)
In the suspension system 10, each of the actuators 30 included in the four spring absorber assemblies 20 can be independently controlled. In each of the spring absorber assemblies 20, the actuator force of the actuator 30 is independently controlled, and standard control as the first control based on a predetermined rule is executed. More specifically, control for attenuating vibrations of the vehicle body and the wheels 12, that is, sprung vibration and unsprung vibration (hereinafter sometimes referred to as “vibration damping control”), and rolling of the vehicle body caused by turning of the vehicle. Control for suppressing (hereinafter sometimes referred to as “roll suppression control”), control for suppressing the pitch of the vehicle body caused by acceleration / deceleration of the vehicle (hereinafter also referred to as “pitch suppression control”), Control executed in parallel. In the vibration damping control, roll suppression control, and pitch suppression control, the actuator force to be generated by the actuator 30 is determined by adding the vibration damping component, roll suppression component, and pitch suppression component, which are the components of the actuator force for each control. Then, the actuator 30 is controlled so as to generate an actuator force having the determined magnitude. In the following description, the actuator force and its component have a positive value corresponding to the force in the direction in which the sprung portion and the unsprung portion approach (bound direction), and the direction that separates the sprung portion and the unsprung portion. It is assumed that the force corresponding to the (rebound direction) force is a negative value.

a) Vibration damping control In the vibration damping control, a vibration damping component F _V of the actuator force is determined so as to generate an actuator force having a magnitude corresponding to the vibration speed in order to attenuate the vibration of the vehicle body and the wheel 12. . In other words, the control is based on both the control based on the so-called skyhook damper theory and the control based on the pseudo groundhook damper theory. Specifically, the vertical operating speed of the vehicle body mount 24 obtained from the spring vertical acceleration detected by the spring vertical acceleration sensor 174 provided on the vehicle mount 24, the so-called absolute spring speed Vs. Based on the vertical movement speed of the wheel 12 obtained from the unsprung longitudinal acceleration detected by the unsprung longitudinal acceleration sensor 176 provided on the lower arm 22, the so-called unsprung absolute speed Vg, vibration damping is performed according to the following equation: The component F _V is calculated.
F _V = Cs · Vs−Cg · Vg
Here, Cs is a gain for generating a damping force in accordance with the vertical operation speed of the mount 24 of the vehicle body, and Cg generates a damping force in accordance with the vertical operation speed of the wheel 12. For gain. That is, Cs and Cg can be considered as damping coefficients for so-called sprung and unsprung absolute vibrations.

b) Roll suppression control When the vehicle turns, the roll moment resulting from the turn separates the sprung and unsprung parts on the turning inner ring side and causes the sprung and unsprung parts on the turning outer ring side to approach each other. It is done. In the roll suppression control, in order to suppress the separation on the turning inner ring side and the approach on the turning outer ring side, the actuator force in the bounce direction is applied to the actuator 30 on the turning inner ring side, and the actuator force in the rebound direction is applied to the actuator 30 on the turning outer ring side. Each is generated as a roll restraining force. Specifically, first, as a lateral acceleration indicating a roll moment received by the vehicle body, an estimated lateral acceleration Gyc estimated based on the steering angle δ of the steering wheel and the vehicle speed v, and a lateral acceleration sensor 172 were measured. Based on the actual lateral acceleration Gyr, a control lateral acceleration Gy ^* , which is a lateral acceleration used for control, is determined according to the following equation.
Gy ^* = K ₁ · Gyc + K ₂ · Gyr (K ₁ , K ₂ : gain)
Such based on the determined control-use lateral acceleration Gy ^*, the roll restrain component F _R is determined according to the following equation.
F _R = K ₃ · Gy ^* (K ₃ : Gain)

c) Pitch suppression control When a vehicle nose dive occurs during deceleration such as when the vehicle is braked, the front wheel side spring top and spring bottom are brought closer to each other by the pitch moment that generates the nose dive. The sprung part on the ring side and the unsprung part are separated from each other. In addition, when squat of the vehicle body is generated during acceleration of the vehicle, the sprung moment that generates the squat separates the front wheel spring top and the spring bottom, and the rear wheel spring top and spring bottom. Is approached. In the pitch suppression control, the actuator force is generated as the pitch suppression force in order to suppress fluctuations in the distance between the sprung springs in those cases. Specifically, as longitudinal acceleration indicative of the pitch moment acting on the vehicle body, is employed the actual longitudinal acceleration Gx that is actually measured by the longitudinal acceleration sensor 170, and based on the actual longitudinal acceleration Gx, the pitch restrain component F _P has the following formula Determined according to.
F _P = K ₄ · Gx (K ₄ : Gain)
The pitch suppression control is executed when the throttle opening detected by the throttle sensor 178 or the master cylinder pressure detected by the brake pressure sensor 180 exceeds a set threshold.

d) Target Actuator Force and Motor Operation Control The control of the actuator 30 in the standard control is performed based on the standard actuator force F _A which is the actuator force to be generated. In detail, as described above, the vibration damping component F _V of the actuator force, a roll restrain component F _R, the pitch restrain component F _P is determined on the basis of their, standard actuator force F _A according to: determine Is done.
F _A = F _V + F _R + F _P
Then, the standard actuator force F _A determined as described above is set as the target actuator force F ^*, and the inverter 146 performs operation control of the motor 44 for generating the target actuator force F ^* . More specifically, a target duty ratio is determined based on the target actuator force F ^* described above, and a command based on the duty ratio is transmitted to the inverter 146. Under the appropriate duty ratio, the inverter 146 controls the opening and closing of the switching element included in the inverter 146 to operate the motor 44 so as to generate the target actuator force F ^* .

ii) Short-circuit braking control (second control)
For example, when the amount of charge (remaining capacity) of the battery 150 decreases, the electric power required by the battery 150 cannot be supplied to each of the actuators 30, and the actuator force having a magnitude that is targeted by the four actuators 30. May not occur. Therefore, in the present suspension system 10, when the remaining energy amount E of the battery 150 detected by the charge amount sensor 182 becomes smaller than the set value E ₀ , the four actuators 30 are replaced with the standard control described above. The short-circuit braking control is executed as the second control in which the current-carrying terminals of the respective phases of the motor 44 corresponding to all of the above are short-circuited to generate the actuator force as the braking force. That is, in the present system 10, the inverter 146 as a drive circuit functions as a conduction / non-conduction switch.

Specifically, in the short-circuit braking control, all the high-side switching elements HUS, HVS, and HWS of the inverter 146 are turned on (closed state), and all the low-side switching elements LUS, LVS, and LWS are turned off. (Open state), the switching elements HUS, HVS, HWS and the free-wheeling diodes arranged in parallel to them are in a state where the current-carrying terminals of each phase of the motor 44 are short-circuited to each other. It is. Due to the short-circuit braking control, an electromotive force is generated in the motor 44 under a situation where the remaining energy amount E of the battery 150 is smaller than the set value E ₀ , and an actuator force depending on the electromotive force is generated. The actuator force can be estimated as a braking force having a magnitude according to the short-circuit characteristic line shown in FIG. 4 according to the rotational speed ω of the motor 44. That is, the actuator force F _S that is generated by the actuator 30 in the short-circuit braking control can be estimated according to the following equation.
F _S = C · ω (C: damping coefficient during short circuit)
Incidentally, the rotational speed ω of the motor 44 can be obtained from the detection result of the resolver 192 provided in the motor 44.

Next, consider a case where a wheel passes through a convex or concave portion of a road surface. For example, when passing through the convex portion of the road surface, the unsprung portion is moved upwards vigorously and the unsprung portion and the unsprung portion approach each other, in other words, the actuator 30 contracts. At that time, a very large electromotive force is generated in the motor 44, and a large load is applied to the converter 148, the battery 150, and the like. Therefore, under the situation where the unsprung portion is operated vigorously, the above-described short-circuit braking control is performed, and the connection between the power source and each of the four inverters 146 is disconnected by a switch not shown. It has become. Specifically, when the unsprung longitudinal acceleration Gzg detected by the unsprung longitudinal acceleration sensor 176 exceeds the set value G ₀ , the standard control is switched to the short-circuit braking control.

iii) Control during control switching For example, if the remaining energy amount E of the battery 150 is less than the set value E ₀ and the above-described short-circuit braking control is executed, the power consumption by the actuator 30 is reduced to zero and the vehicle The battery 150 is charged by a charging device (not shown) mounted on the battery. For this reason, the normal state is restored from the situation where the remaining energy E of the battery 150 is smaller than the set value E ₀ . Therefore, when the remaining energy amount E of the battery 150 becomes equal to or greater than the set value E ₀ , the control is returned to the standard control. In addition, the situation where the unsprung part can be vigorously operated is temporary, such as when traveling on rough roads or passing through unevenness on the road surface, so even when it disappears under that situation, Return to standard control. Incidentally, if the unsprung vertical acceleration Gzg is running short brake control exceeds the set value G _0, during the set time T, when the state unsprung vertical acceleration Gzg is equal to or smaller than the set value G ₀ is continued Return to standard control.

However, if the short-circuit braking control is instantaneously returned to the standard control, the passenger feels uncomfortable due to a sudden change in control or a sudden change in actuator force. Therefore, in the present suspension system 10, when switching from short-circuit braking control to standard control, control switching control is executed for a set time t ₀ (for example, several seconds) before switching to standard control. It has become so. A control switching control, and the standard actuator force F _A as a first control when the actuator force actuator 30 is an actuator force to be generated when the standard control mentioned above is performed, short-circuit braking control is executed In this case, the control is performed at the time of this control switching by weighting and adding each of them based on the short-circuit actuator force F _S as the actuator force at the time of the second control, which is the actuator force that the actuator 30 will generate when The actuator force to be generated at is determined. Specifically, with the passage of time, the weight of the short-circuit actuator force F _S is decreased and the weight of the standard actuator force F _A is increased to determine the target actuator force F ^* in the control switching control.

Specifically, when the above-described condition for returning to the standard control is satisfied while the short-circuit braking control is being executed, the weighting coefficient α of the standard actuator force F _{A with} respect to the short-circuit actuator force F _S is used. Thus, the target actuator force F ^* is determined according to the following equation.
F ^* = (1-α) F _S · + α · F _A
The weighting coefficient α is determined as shown in FIG. 5 with respect to the elapsed time t from the time point when the above conditions are satisfied, and gradually changes from 0 to 1. In other words, the ratio of the standard actuator force F _{A to} the short-circuit actuator force F _S is gradually increased over time by the control switching control, and in this system 10, the short-circuit braking control is gradually changed to the standard control. Will be changed. Therefore, according to the present system 10, the actuator force does not change suddenly with the switching of the control described above, and the switching from the short-circuit braking control to the standard control is performed smoothly. Can be suppressed.

The control switching control is not executed at the time of switching from the standard control to the short-circuit braking control. Under the above-described situation where the residual energy amount E of the battery 150 is less than the set value E ₀ , In order to quickly cope with the situation where the engine is vigorously operated, the control is instantaneously switched to the short-circuit braking control.

<Control program>
The control of the actuator 30 as described above is performed by the actuator control program shown in the flowchart of FIG. 6 with a short time interval Δt (for example, several milliseconds to several tens of milliseconds) while the ignition switch 160 is in the ON state. This is performed by being repeatedly executed by the ECU 140. The control flow will be briefly described below with reference to the flowchart shown in the figure. The actuator control program is executed for each actuator 30 of the spring absorber assembly 20 provided on each of the four wheels 12. In the following description, processing by a program for one actuator 30 will be described in consideration of simplification of description.

  In the processing by the actuator control program, an execution control flag FL indicating which control is executed between the standard control as the first control and the short-circuit braking control as the second control is employed. The value is set to 0 when executing standard control, and is set to 1 or 2 when executing short-circuit braking control. In addition, although demonstrated in detail later, when performing short circuit braking control, it is set to 1 or 2 according to the factor which performed that control.

In the processing according to this program, first, in step 1 (hereinafter abbreviated as “S1”, the same applies to other steps), the standard actuator force F _A is determined by the standard actuator force determination subroutine shown in the flowchart of FIG. Done by being executed. Determination processing of the standard actuator force F _A is the method as described above, in S21 to S23, the vibration suppression component F _V, the roll restrain component F _R, pitch restrain component F _P is determined, these three components Is added to determine the standard actuator force F _A.

Next, in S2 to S5, it is determined which of standard control, short-circuit braking control, and control switching control is to be executed. Normally, standard control is executed in S7, and the standard actuator force F _A determined in S1 is set as the target actuator force F ^* . Subsequently, in S18, a duty ratio for controlling the motor 44 is determined based on the target actuator force F ^* , and a command based on the duty ratio is transmitted to the inverter 146. By this process, the operation of the motor 44 of each actuator 30 is controlled, so that each actuator 30 generates the required actuator force.

Further, in S2, whether or not the remaining energy amount E of the battery 150 detected less than the set value E ₀ is determined by the charge amount sensor 182, in S3, unsprung acceleration Gzg detected by the unsprung vertical acceleration sensor 176 Is greater than the set value G ₀ . When the remaining energy amount E becomes smaller than the set value E _0, the flag value of the execution control flag FL is set to 1 in S8, and short-circuit braking control is executed in S10. In other words, in order to short-circuit the current-carrying terminals of each phase of the motor 44 of the actuator 30, the switching elements HUS, HVS, HWS on the high side are all in the ON state as described above. (Closed state), and a control signal for turning off all the low-side switching elements LUS, LVS, and LWS (open state) is transmitted to the inverter 146. When the unsprung acceleration Gzg is larger than the set value G ₀ , the flag value of the execution control flag FL is set to 2 in S9, and short-circuit braking control is executed in S10.

The short-circuit braking control described above is returned to the standard control when it is determined in S2 that the remaining energy amount E has become equal to or greater than the set value E ₀ and in S5 that the flag value of the execution control flag FL is determined to be 1. Accordingly, the control switching control at S13 and subsequent steps is executed. Also, the time counter of S11 and S12, when the state unsprung acceleration Gzg is equal to or smaller than the set value G ₀ is continued for a set time T, S13 following control switching control is performed.

In the control switching control process after S13, first, at S13, when the remaining energy amount E becomes equal to or greater than the set value E ₀ or when the unsprung acceleration Gzg is equal to or less than the set value G ₀ , The elapsed time t from the point of time continued is measured. Until the set time t ₀ elapses, the target actuator force F ^* is determined in S15 to S17. Specifically, in S15, a short-circuit actuator force F _S (= C · ω), which is an actuator force that is generated by the actuator 30 when it is assumed that the short-circuit braking control is executed, is estimated. Next, in S16, the weighting coefficient α between the standard actuator force F _A and the short-circuit actuator force F _S is determined from the map data of the weighting coefficient α with respect to the elapsed time t shown in FIG. In S17, the target actuator force F ^* (= (1-α) F _S · + α · F _A ) is determined based on the standard actuator force F _A , the short-circuit actuator force F _S , and the weighting coefficient α, and the target actuator A command value determined based on force F ^* is transmitted to inverter 146. If it is determined in S14 that the set time t ₀ has elapsed, the flag value of the execution control flag FL is set to 0 in S6, the elapsed time t and the counter value c are reset, and the process of S7 The standard control is executed, and the standard control that is the normal control is returned.

  10: Vehicle suspension system 12: Wheel 20: Spring absorber assembly 22: Lower arm (lower spring) 24: Mount part (upper spring) 30: Actuator 32: Coil spring (suspension spring) 44: Electromagnetic motor 140: Suspension electronic control Unit (ECU, control device) 146: Inverter (drive circuit, conduction / non-conduction switching device) 148: Converter [CONV] 150: Battery [BAT] 176: Unsprung vertical acceleration sensor [Gzg] 182: Charge amount sensor [E 192: Resolver [θ]

F _V : Vibration damping component F _R : Roll suppression component F _P : Pitch suppression component F _A : Standard actuator force (actuator force during first control) F ^* : Target actuator force E: Residual energy amount (charge amount) F _S : Short-circuit actuator force (actuator force during second control) C: Damping coefficient during short-circuit ω: Motor rotation speed Gzg: Unsprung longitudinal acceleration α: Weighting coefficient

Claims (4)

An actuator having an electromagnetic motor and generating an actuator force that is a force in a direction in which they approach and separate from the upper and lower springs depending on the force generated by the electromagnetic motor;
Allowing the current flow from the power supply to the electromagnetic motor without conducting the mutual conduction between the current-carrying terminals and the current-carrying state between the current-carrying terminals of each phase of the electromagnetic motor of the actuator. A conduction / non-conduction switching device for switching between the terminal non-conduction states;
A control device for controlling the actuator and the conduction / non-conduction switch, wherein (A) the conduction / non-conduction switch realizes a non-terminal state between the terminals and determines the actuator force generated by the actuator. A first control for controlling based on the determined rules; (B)
A second control for generating an actuator force generated by the actuator as a braking force having a magnitude depending on an electromotive force generated in an electromagnetic motor by realizing a terminal-to-terminal conduction state by the conduction / non-conduction switch; A vehicle suspension system comprising a control device that executes selectively,
The control device is
When switching from one of the first control and the second control to the other of the first control and the second control, a non-conduction state between terminals is realized by the conduction / non-conduction switch, and the first control When the control is executed, the first control time actuator force that is the actuator force to be generated by the actuator and when the second control is executed the second control time is the actuator force that the actuator generates. Based on the actuator force, each of them is weighted and added to determine a target actuator force that is an actuator force to be generated by the actuator, and the actuator is set to the determined target actuator force. as but executing the control switching control for controlling the actuator force to be generated It is composed,
The control when switching is
( i) When switching from the first control to the second control, the weight of the actuator force at the time of the second control is increased and the weight of the actuator force at the time of the second control is increased with the passage of time. ii) When switching from the second control to the first control, the weight of the actuator force during the second control is decreased with the passage of time, while the weight of the actuator force during the second control is decreased, A vehicle suspension system configured to determine a target actuator force and to control an actuator force generated by the actuator so as to be the determined target actuator force . The control device is
2. The vehicle suspension according to claim 1, wherein the control switching control is not executed when switching from the first control to the second control but is executed only when switching from the second control to the first control. system. The control device is
The first control is executed, the vehicle suspension system of claim 1 or claim 2 executes the second control in a situation such as the unsprung portion is force caused often operate in normal. The control device is
The vehicle suspension system according to the first control executed in the normal, any one of claims 3 to claims 1 executes the second control in fewer situations than the remaining energy amount of the power set value.

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