JP4211327B2 - Driving safety support device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle travel safety support device that avoids contact with an object based on a relative positional relationship and relative speed with an object detected in front of the host vehicle by an object detection device such as a laser radar.
[0002]
[Prior art]
When the vehicle is running almost straight and there is a high possibility of contact with the preceding vehicle, it is very effective to perform contact avoidance control, but the driver is sufficient when changing corners or lanes. Therefore, if the contact avoidance control is performed at the same timing as during the normal traveling, drivability is poor and the driver feels uncomfortable.
[0003]
For example, Japanese Unexamined Patent Application Publication No. 2002-002426 discloses a vehicle travel safety support device that solves such a problem. This driving safety support device automatically activates the contact avoidance control based on a predetermined time (collision time) before contact, and further, when detecting that the vehicle is turning, By correcting the threshold value for determining the collision time to be small, the intervention of the contact avoidance control is delayed, the operation frequency of the contact avoidance control is reduced, and the drivability is improved.
[0004]
[Problems to be solved by the invention]
However, although the intervention of the contact avoidance control can be delayed by correcting the threshold value, the intervention of the contact avoidance control may be performed at a shorter intervehicular distance than the case where such correction is not performed. Therefore, the braking deceleration for avoiding contact with the preceding vehicle is increased. This makes the driver feel uncomfortable.
[0005]
In addition, the contact avoidance intervention timing is based on the collision time, that is, the contact avoidance control is performed using only the time as an index of the possibility of contact, so the relative speed is small and the own vehicle gradually becomes the preceding vehicle. When approaching, the technique described in Japanese Patent Laid-Open No. 2002-002426 eliminates contact avoidance control intervention.
[0006]
Therefore, the present invention has been made in view of the above problems, and when the vehicle is in a turning state, the contact avoidance control is intervened at the optimum timing, and the driver does not feel uncomfortable by the intervening control avoidance control. An object of the present invention is to provide a driving safety support device that can handle such a situation.
[0007]
[Means for Solving the Problems]
  To solve the problem,The present inventionIn a travel safety support device that operates braking control that avoids vehicle contact with an object at a predetermined timing, the relative distance between the vehicle and an object in front of the vehicle is obtained by dividing by the vehicle speed of the vehicle. A threshold set by the first contact possibility index corresponding to the first contact possibility indexBelowThe second contact possibility index obtained by performing the braking control or dividing the relative distance between the vehicle and an object ahead of the vehicle by the relative speed between the vehicle and the object is Threshold value set corresponding to 2 contact possibility indexBelowThe brake control is performed, and the two brake controls are selectively performed,Change meansWhen the vehicle is in a turning state, a threshold value set corresponding to the first contact possibility indexAnd change beforeThe threshold set by the second contact possibility index corresponding to the second contact possibility indexBelowControl gain of braking controlChangeChange.The control gain increases the braking force of the braking control as the value increases, and the change means increases the steering angle change amount indicating the turning state of the vehicle. While the threshold value set corresponding to the contact possibility index is decreased, the control gain is increased as the rudder angle change amount indicating the turning state of the vehicle increases.
[0009]
【The invention's effect】
  According to the present invention,The braking control for avoiding contact can prevent the driver from feeling uncomfortable.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows the configuration of a vehicle equipped with a travel safety support device according to the present invention. FIG. 2 shows a configuration of the control controller 10 that performs each control of the vehicle.
As shown in FIG. 1, a radar 1, a steering angle sensor 2, and a wheel speed sensor 3 for each wheel are mounted on the vehicle. The radar 1 is for recognizing an object ahead of the host vehicle, and is, for example, a millimeter wave type radar or a laser type radar. The steering angle sensor 2 is for detecting the steering angle of the steering wheel 4. The wheel speed sensor 3 is a sensor that detects the vehicle speed and outputs a pulse signal S2 according to the speed of the wheel 5. The sensor signals S 1, S 3 and S 2 of the radar 1, the steering angle sensor 2 and the wheel speed sensors 3 are input to the controller 10.
[0012]
The controller 10 controls each component of the vehicle. The driving safety support is realized by the contact avoidance control by the controller 10, and the following controller 10 will be described focusing on the contact avoidance control process.
As shown in FIG. 2, the controller 10 includes a first contact possibility index calculation unit 11, a second contact possibility index calculation unit 12, and a calculation unit 13 as a configuration for realizing contact avoidance control. Yes. The process of the controller 10 having such a configuration will be described with reference to FIG.
[0013]
First, in step S <b> 1, various signals are input to the controller 10. That is, the controller 10 detects the vertical distance (traveling direction) relative distance, the vertical relative speed, and the horizontal relative distance from the signal S1 from the radar 1 with the preceding vehicle. When the relative speed cannot be directly detected, the relative speed may be calculated from the relative distance. Further, the controller 10 calculates the speed of the host vehicle from the pulse signal S2 output from the wheel speed sensor 3 of each wheel 5. Furthermore, the controller 10 detects the steering operation state of the steering wheel 4 from the signal S3 from the steering angle sensor 5. Then, the controller 10 detects the winker operating state from the switch switching signal S4 of the winker selector switch 6.
[0014]
And the controller 10 calculates the brake fluid pressure command value output to the brake control unit 21 based on each information obtained by the process after step S2.
First, in step S2, the controller 10 determines the first threshold value THW for the first contact possibility index THW.^*Is calculated. First threshold THW^*Is determined as follows.
[0015]
FIG. 4 shows the first threshold THW on the vertical axis.^*The steering angle change amount is taken on the horizontal axis, and the first threshold value THW for the steering angle change amount is taken.^*The characteristic figure of is shown. For example, the rudder angle change amount is a value obtained based on the rudder angle time change amount detected by the rudder angle sensor 2, and the calculation unit 13 receives a sensor signal S3 from the rudder angle sensor 2 as shown in FIG. Is the value obtained from As shown in FIG. 4, the first threshold value THW increases as the rudder angle change amount increases.^*Decreases after a certain steering angle change amount, the first threshold THW^*Becomes a constant characteristic.
[0016]
Based on such a characteristic diagram, the first threshold THW corresponding to the steering angle change amount^*To decide. That is, when the vehicle is not in a turning state, the value when the steering angle change amount is 0 is set to the first threshold value THW.^*When the vehicle is in a turning state, a value corresponding to the steering angle change amount after 0 is set as the first threshold value THW.^*As determined.
Note that the first threshold value THW increases as the rudder angle change amount increases.^*In the region where the decrease occurs, the inclination may be changed according to the vehicle speed of the host vehicle.
[0017]
In step S3, the controller 10 calculates a first brake fluid pressure command value F_thw for the first contact possibility index THW. That is, first, the first contact possibility index calculating unit 11 calculates the first contact possibility index THW by the following equation (1) using the speed of the host vehicle obtained as described above.
THW = L / V_C  ... (1)
Where L is the relative distance and V_CIs the vehicle speed. A value obtained from such a relational expression is a value generally called an inter-vehicle time.
[0018]
And the 1st contact possibility parameter | index calculation part 11 calculates the 1st brake fluid pressure command value F_thw by the following (2) Formula using this 1st contact possibility parameter | index THW.
F_thw = G_thw × (THW−THW^*(2)
Here, G_THW is a control gain corresponding to the first contact possibility index THW. The first threshold THW^*Is a value obtained according to the steering angle change amount from the relationship shown in FIG.
[0019]
The equation (2) is defined as a negative value. That is, (THW−THW in the equation (2).^*) Is defined as zero if the value is positive. In this way, the first contact possibility index THW becomes the first threshold THW.^*(THW> THW)^*), It is not controlled by the first contact possibility index THW.
[0020]
In other words, the first brake fluid pressure command value F_thw has the first contact possibility index THW equal to the first threshold value THW.^*It is a value that is defined to occur as a usable control value when the value falls below. That is, the first brake fluid pressure command value F_thw is determined based on the vehicle speed V V based on the relationship of the first contact possibility index THW defined by the equation (1)._CIs a value defined so as to be generated as a control value that can be used when the relative distance L is small.
[0021]
On the other hand, in step S4, the controller 10 calculates a control gain G_ttc for the second contact possibility index TTC. The control gain G_ttc is determined as follows. FIG. 5 shows a characteristic diagram of the control gain G_ttc with respect to the steering angle change amount, with the control gain G_ttc on the vertical axis and the aforementioned steering angle change amount on the horizontal axis. As shown in FIG. 5, the control gain G_ttc increases as the rudder angle change amount increases, and after a certain rudder angle change amount, the control gain G_ttc becomes a constant characteristic. Based on such a characteristic diagram, a control gain G_ttc corresponding to the steering angle change amount is determined. That is, when the vehicle is not turning, the value when the rudder angle change amount is 0 is determined as the control gain G_ttc, and when the vehicle is turning, the value corresponding to the rudder angle change amount after 0 is controlled. The gain is determined as G_ttc.
[0022]
In step S5, the controller 10 calculates a second brake fluid pressure command value F_ttc for the second contact possibility index TTC. That is, first, the second contact possibility index calculation unit 12 uses the vertical relative speed and the speed of the host vehicle obtained as described above, and uses the following formula (3) to calculate the second contact possibility index. TTC is calculated.
[0023]
TTC = L / ΔV (3)
Here, L is a relative distance, and ΔV is a relative speed between the host vehicle and the preceding vehicle. A value obtained from such a relational expression is a value generally called vehicle head time.
And the 2nd contact possibility parameter | index calculation part 12 calculates the 2nd brake hydraulic pressure command value F_ttc by following (4) Formula using this 2nd contact possibility parameter | index TTC.
[0024]
F_ttc = G_ttc × (TTC−TTC^*(4)
Where TTC^*Is a threshold value for the second contact possibility index TTC. This second threshold TTC^*Is a fixed predetermined value. The control gain G_ttc is a value obtained according to the steering angle change amount from the relationship shown in FIG.
The equation (4) is defined as a negative value. That is, (TTC-TTC in the equation (4).^*) Is defined as zero if it is positive. In this way, the second contact possibility index TTC becomes the second threshold value TTC.^*Greater than (TTC> TTC^*) And not controlled by the second contact possibility index TTC.
[0025]
That is, the second brake fluid pressure command value F_ttc is determined by the second contact possibility index TTC as the second threshold value TTC.^*It is a value that is defined to occur as a usable control value when the value falls below. That is, the second brake fluid pressure command value F_ttc can be used when the relative speed ΔV is large or the relative distance L is small, based on the relationship of the second contact possibility index TTC defined by the equation (3). It is a value defined to be generated as a control value.
[0026]
Subsequently, in step S6, the controller 10 selects one of the first brake fluid pressure command value F_thw and the second brake fluid pressure command value F_ttc calculated in steps S3 and S5. Specifically, it is determined whether or not the first brake fluid pressure command value F_thw is smaller than the second brake fluid pressure command value F_ttc (F_thw <F_ttc).
[0027]
In this determination, when the first brake fluid pressure command value F_thw is smaller than the second brake fluid pressure command value F_ttc, that is, the first brake fluid pressure command value F_thw is greater than the second brake fluid pressure command value F_ttc. If the absolute value is too large, the process proceeds to step S7 where the final brake fluid pressure command value F is set to the first brake fluid pressure command value F_thw (F = F_thw), while the first brake fluid pressure command value F_thw is the second value. Is greater than or equal to the brake fluid pressure command value F_ttc, that is, if the first brake fluid pressure command value F_thw is smaller than the second brake fluid pressure command value F_ttc as an absolute value, the process proceeds to step S8 and the final brake fluid pressure The command value F is set to the second brake fluid pressure command value F_ttc (F = F_ttc), and the process is terminated.
[0028]
The processing of step S6, step S7 and step S8 is performed by the calculation unit 13.
The first and second contact possibility index calculation units 11 and 12 are based on the relationship between the own vehicle and the preceding vehicle that is an object ahead of the own vehicle and the behavior of the own vehicle. An evaluation means for evaluating the possibility of contact with the preceding vehicle is configured. Further, the processing of the step S3, step S5, step S6, step S7 and step S8 realizes a braking control means for performing braking control as contact avoidance control based on the evaluation result of such an evaluation means, and In the processes of Step S2 and Step S4, when the host vehicle is in a turning state, the timing of the braking control is delayed or the control gain of the braking control is larger than when the vehicle is in a straight traveling state. Thus, changing means for changing is configured.
[0029]
As described above, the controller 10 determines the final brake fluid pressure command value F by the process for driving safety support. The controller 10 then outputs this final brake fluid pressure command value F to the brake control unit 7.
The brake control unit 7 controls the braking device 8 of each wheel 5 based on the final brake fluid pressure command value F. The braking device 8 is a brake caliper or the like, and the brake control unit 7 operates such a braking device 8 based on the brake fluid pressure command value F to perform braking control.
[0030]
Next, the vehicle operation realized based on the above contact avoidance control and the effect thereof will be described.
First, the operation of the vehicle in a normal running state where the vehicle is not in a turning state will be described.
FIG. 6 shows the vehicle operation when the contact avoidance control intervenes based on the first contact possibility index THW, and FIG. 7 shows the case where the contact avoidance control intervenes based on the second contact possibility index TTC. The vehicle operation is shown.
[0031]
Since the vehicle is not in a turning state, the first threshold value THW^*4 is a value when the rudder angle change amount is 0 in the characteristic diagram of FIG. 4, and the control gain G_ttc is a value when the rudder angle change amount is 0 in the characteristic diagram of FIG. 5 (steps S2 and S4). ).
First, the vehicle operation when the contact avoidance control intervenes based on the first contact possibility index THW will be described with reference to FIG.
[0032]
Here, the host vehicle 101 travels at a vehicle speed of 100 km / h, the preceding vehicle 102 travels at a vehicle speed of 95 km / h, and the relative speed ΔV is small, but in FIG. 6 (A) to FIG. As shown as a change to), the host vehicle 101 is in an approaching state to the preceding vehicle 102 after a certain time.
When the host vehicle 101 approaches the preceding vehicle 102 to some extent, the first contact possibility index THW obtained by the equation (1) is the first threshold value THW.^*The first brake fluid pressure command value F_thw obtained from the first contact possibility index THW is generated (step S3).
[0033]
On the other hand, the relative speed ΔV is small, and under this condition, the second contact possibility index TTC obtained by the equation (3) is the second threshold value TTC.^*If it does not fall below, the second brake fluid pressure command value F_ttc based on the second contact possibility index TTC will not be generated (step S5).
Here, this relationship will be described in a section indicated by an arrow A1 or an arrow A2 forward from the host vehicle 101 shown in FIG.
[0034]
A section indicated by an arrow A1 or an arrow A2 forward from the host vehicle 101 is equivalent to a threshold value indicated by a relative relationship with a contact possibility index using an inter-vehicle distance as an index. That is, the first contact possibility index THW is calculated based on the equation (1) from the inter-vehicle distance L and the own vehicle speed V._CFunction (THW = L / V_C) And therefore the vehicle speed V_CIs constant, the first contact possibility index THW is a value that varies with the inter-vehicle distance L as a variable. On the other hand, the second contact possibility index TTC is expressed as a function of the inter-vehicle distance L and the relative speed ΔV (TTC = L / ΔV) from the equation (2). Therefore, when the relative speed ΔV is constant, The contact possibility index TTC of 2 is a value that changes with the inter-vehicle distance L as a variable.
[0035]
Therefore, from this relationship, the vehicle speed V_CIs large, even if the inter-vehicle distance L is large, the first contact possibility index THW is equal to the first threshold value THW.^*Vice versa, the vehicle speed V_CIs small, the first contact possibility index THW is equal to the first threshold value THW.^*In order to fall below, the inter-vehicle distance L needs to be reduced accordingly. That is, for example, own vehicle speed V_CIs small, the first contact possibility index THW is the first threshold value THW as long as the own vehicle 101 does not approach the preceding vehicle 102 accordingly.^*Never fall below.
[0036]
On the other hand, when the relative speed ΔV is large, even if the inter-vehicle distance L is a large value, the second contact possibility index TTC is the second threshold value TTC.^*On the contrary, when the relative speed ΔV is small, the second contact possibility index TTC is equal to the second threshold value TTC.^*In order to fall below, the inter-vehicle distance L needs to be reduced accordingly. That is, for example, when the relative speed ΔV is small, the second contact possibility index TTC is the second threshold value TTC unless the host vehicle 101 approaches the preceding vehicle 102 accordingly.^*Never fall below.
[0037]
For this reason, the section indicated by the arrow A1 or the arrow A2 forward from the host vehicle 101 is equivalent to a threshold value indicated by a relative relationship with the contact possibility index using the inter-vehicle distance L as an index.
Therefore, as in this example, the vehicle speed V_CHowever, since the relative speed ΔV is small, the second threshold TTC^*The section indicated by the arrow A2 corresponding to the first threshold THW^*As a result, the preceding vehicle 102 enters the section indicated by the arrow A1 before the section indicated by the arrow A2, and the inter-vehicle distance L at this time is equal to the first threshold THW.^*The inter-vehicle distance L is such that a first contact possibility index THW that is less than 1 is obtained.
[0038]
From the above relationship, the first brake fluid pressure command value F_thw is generated by the first contact possibility index THW.
Then, the first brake fluid pressure command value F_thw is given as the final brake fluid pressure command value F (steps S6 and S7), and the final brake fluid pressure command value F_thw which is the first brake fluid pressure command value F_thw. Thus, deceleration control of the host vehicle 101 is performed.
[0039]
This deceleration control acts as an effect of prompting the driver to perform an avoiding operation such as a brake operation or a steering wheel operation. That is, since the deceleration control notifies the driver that there is a possibility of contact, the driver can perform avoidance operations such as a brake operation and a steering wheel operation with a margin.
Thus, the first contact possibility index THW is the first threshold value THW.^*By generating the first brake fluid pressure command value F_thw obtained by the first contact possibility index THW, that is, the host vehicle speed V_CBy evaluating the possibility of contact using the first contact possibility index consisting of the so-called inter-vehicle time as a function, even if the host vehicle approaches the preceding vehicle in a state where the relative speed is low, While performing avoidance control, the driver can be notified of the possibility of contact with the preceding vehicle.
[0040]
Next, the operation of the vehicle when the contact avoidance control based on the second contact possibility index TTC intervenes will be described with reference to FIG.
Here, the host vehicle 101 travels at a vehicle speed of 100 km / h, the preceding vehicle 102 travels at a vehicle speed of 80 km / h, and the relative speed ΔV is large. From FIG. 7A to FIG. 7B As shown as a change to, the host vehicle 101 enters an approaching state to the preceding vehicle 102 after a certain time.
[0041]
When the host vehicle 101 approaches the preceding vehicle 102 to some extent, the second contact possibility index TTC obtained by the equation (2) is the second threshold value TTC.^*Is below the second brake fluid pressure command value F_ttc obtained by the second contact possibility index TTC (step S5).
On the other hand, under this condition, the first contact possibility index THW obtained by the equation (1) is the first threshold value THW.^*If it does not fall below, the first brake fluid pressure command value F_thw based on the first contact possibility index THW will not be generated (step S3).
[0042]
That is, since the relative speed ΔV is large, the first threshold value THW^*The section indicated by the arrow A1 corresponding to the second threshold value TTC^*As a result, the preceding vehicle 102 enters the section indicated by the arrow A2 before the section indicated by the arrow A1, that is, the inter-vehicle distance L is equal to the second threshold value TTC.^*The second brake fluid pressure command value F_ttc is generated based on the second contact possibility index TTC by obtaining the inter-vehicle distance L such that the second contact possibility index TTC is less than.
[0043]
Accordingly, the final brake fluid pressure command value F is given as the second brake fluid pressure command value F_ttc (steps S6 and S8), and the final brake fluid pressure command value F_ttc is the final brake fluid pressure command value F_ttc. Thus, deceleration control of the host vehicle 101 is performed.
This deceleration control acts as an effect of prompting the driver to perform an avoiding operation such as a brake operation or a steering wheel operation. That is, since the deceleration control notifies the driver that there is a possibility of contact, the driver can perform avoidance operations such as a brake operation and a steering wheel operation with a margin.
[0044]
Thus, the second contact possibility index TTC is the second threshold value TTC.^*By generating a second brake fluid pressure command value F_ttc obtained by the second contact possibility index TTC, that is, a second contact comprising a so-called vehicle head time as a function of the relative speed ΔV. By evaluating the possibility of contact using the possibility index, when the vehicle approaches the preceding vehicle with a large relative speed, contact avoidance control is performed as driving safety support, and the driver is informed of the preceding vehicle. The possibility of contact can be informed.
[0045]
Next, the operation of the vehicle when the vehicle is in a turning state will be described.
FIG. 8 shows the operation of the vehicle when the contact avoidance control intervenes based on the first contact possibility index THW, FIG. 9 is a comparative example of FIG. 8, and FIG. 10 shows the second contact possibility. The operation of the vehicle when the contact avoidance control intervenes based on the sex index TTC is shown.
Since the vehicle is in a turning state, the first threshold value THW^*4 is a value when the rudder angle change amount is larger than 0 in the characteristic diagram of FIG. 4, and the control gain G_ttc is a value when the rudder angle change amount is larger than 0 in the characteristic diagram of FIG. S2 and step S4).
[0046]
First, the operation of the vehicle when the contact avoidance control intervenes based on the first contact possibility index THW will be described with reference to FIGS.
Here, as in FIG. 6, the host vehicle 101 travels at a vehicle speed of 100 km / h, the preceding vehicle 102 travels at a vehicle speed of 95 km / h, and although the relative speed ΔV is small, ) To (B) in FIG. 8, the host vehicle 101 approaches the preceding vehicle 102 after a certain time.
[0047]
Then, as shown in FIG. 8B, when the host vehicle is in the turning state, the first threshold value THW is set as compared with the case of the straight running state.^*Therefore, the host vehicle 101 approaches the preceding vehicle 102 to some extent, and the reduced first threshold value THW is reduced.^*When the first contact possibility index THW obtained by the equation (1) falls below, the first brake fluid pressure command value F_thw obtained by the first contact possibility index THW is generated (the step). S5).
[0048]
That is, the first threshold THW when the vehicle is turning^*The first threshold value TTC when the section indicated by the arrow A1 corresponding to is in a straight running state^*The first brake fluid pressure command value F_thw is generated by the first contact possibility index THW when the preceding vehicle 102 enters the section that is shorter than the section indicated by the arrow A1 corresponding to. I am letting.
[0049]
Thus, the final brake hydraulic pressure command value F is given as the first brake hydraulic pressure command value F_thw (steps S7 and S8), and the final brake hydraulic pressure command value F_thw is the final brake hydraulic pressure command value F_thw. Based on the value F, deceleration control of the host vehicle 101 is performed.
This deceleration control acts as an effect of prompting the driver to perform an avoiding operation such as a brake operation or a steering wheel operation. That is, since the deceleration control notifies the driver that there is a possibility of contact, the driver can perform avoidance operations such as a brake operation and a steering wheel operation with a margin.
[0050]
Furthermore, in the case of the turning state, the first threshold value THW^*The effect of correcting is as follows.
FIG. 9 shows the first threshold value THW even in the turning state.^*The vehicle operation | movement of the comparative example which is fixing is shown. In other words, the vehicle operation when the contact avoidance control intervenes based on the first contact possibility index THW in the turning state is the first threshold value THW.^*This is the vehicle operation when the correction is not performed.
[0051]
In this case, as shown as a change from (A) in FIG. 9 to (B) in FIG. 9, the host vehicle 101 enters an approaching state to the preceding vehicle 102 after a certain time, but the first threshold value THW^*Is fixed, the deceleration control is performed on the preceding vehicle 102 at the same timing as in the normal traveling state (straight line traveling state) even when the lane is changed, and the host vehicle 101 smoothly changes the lane. I can't. In other words, when changing corners or lanes, the driver is paying sufficient attention unlike the normal driving state, so if contact avoidance control is performed at the same timing as the normal driving state, drivability is poor. The driver feels uncomfortable, and as a result, the lane change according to the driver's intention is not made.
On the other hand, when the present invention is applied, the first threshold value THW is applied in the turning state.^*The intervention timing of contact avoidance control is made slower than the intervention timing in the normal driving state, so that the intervention timing becomes the optimal intervention timing that takes into account the driver's attention when changing corners or lanes. The drivability can be improved, and the lane change according to the driver's intention can be realized without making the driver feel uncomfortable.
[0052]
The first threshold THW^*As shown in FIG. 4, the steering angle decreases as the steering angle change amount increases. As described above, the first threshold value THW according to the steering angle change amount at the time of lane change.^*Thus, the intervention timing of the contact avoidance control can be changed according to the steering angle change amount at the time of changing the lane. That is, the larger the rudder angle change amount is, the first threshold THW is.^*As a result, the larger the steering angle change amount, the slower the intervention timing of the contact avoidance control, for example, when the inter-vehicle distance is shorter or the own vehicle speed V_CWill be faster.
[0053]
Further, as described above, the first threshold value THW increases as the rudder angle change amount increases.^*In the region where the decrease occurs, the inclination may be changed according to the vehicle speed of the host vehicle. Specifically, when the vehicle speed is small, the inclination is reduced, that is, the first threshold value THW for the steering angle change amount.^*When the vehicle speed is high, the inclination is increased, that is, the first threshold value THW for the steering angle change amount^*Increase the amount of change.
[0054]
For example, the steering angle change amount decreases as the host vehicle speed increases. This is because the driver operates slowly when changing lanes at high speed, and as a result, the amount of change in rudder angle when changing lanes at high speed is relatively small.
For this reason, when changing lanes at high speed, the first threshold THW for the steering angle change amount^*By increasing the amount of change of the first contact possibility index THW, the first threshold THW^*The intervention timing of the contact avoidance control can be made later.
[0055]
Next, the operation of the vehicle when the contact avoidance control intervenes based on the second contact possibility index TTC will be described.
FIG. 10 shows the operation of the host vehicle 101 when the preceding vehicle 102 decelerates while the host vehicle 101 is turning. As shown as a change from (A) in FIG. 10 to (B) in FIG. 10, if the preceding vehicle 102 decelerates while the own vehicle 101 is changing lanes while the own vehicle 101 approaches the preceding vehicle 102. , The relative speed ΔV increases, and as a result, the second contact possibility index TTC obtained by the equation (3) becomes the second threshold value TTC.^*When the value falls below, a second brake fluid pressure command value F_ttc obtained by the second contact possibility index TTC is generated (step S5).
[0056]
On the other hand, the first threshold value THW due to the turning state^*Therefore, the intervention timing of the contact avoidance control becomes later than the intervention timing in the normal driving state. That is, the first contact possibility index THW obtained by the equation (1) is the first threshold value THW.^*As a result, the first brake fluid pressure command value F_thw based on the first contact possibility index THW is not generated (step S5).
[0057]
As a result, the contact avoidance control is activated by the control gain G_ttc corrected by the turning state. Accordingly, since the contact avoidance control is implemented as strong braking, the driver is informed that there is a possibility of contact because the preceding vehicle 102 has decelerated, and thus the driver can perform braking operation, steering operation, etc. The avoidance operation can be performed with a margin.
[0058]
For example, at the time of lane change, avoidance of preceding vehicles, and merging, the first threshold THW^*And the intervention timing of the contact avoidance control is delayed, so that the contact avoidance control does not intervene unless the relative distance L is reduced to some extent. On the other hand, in such a situation, there is a possibility that the driver's consciousness is far away from the front to confirm left and right. In this case, it is significant to inform the driver that the relative speed has increased in the approaching direction due to deceleration of the preceding vehicle or the like.
[0059]
For this reason, the second threshold value TTC for evaluating the second contact possibility index TTC that is a function of the relative speed ΔV as shown in the equation (3).^*Is fixed so that the intervention timing of the contact avoidance control is not changed, while the contact avoidance control (braking control) is performed with the second brake fluid pressure command value F_ttc in which the control gain G_ttc is changed according to the turning state. As a result, the relative speed ΔV increases and the driver can be notified that the preceding vehicle is approaching.
[0060]
In other words, the first threshold value THW due to the turning state.^*Even if the correction is made in the direction of decreasing the first contact possibility index THW, the first threshold THW^*If the host vehicle 101 approaches the preceding vehicle 102 to a level below the first vehicle 102, the first brake fluid pressure command value F_thw is generated, and contact avoidance control (braking control) is performed using the first brake fluid pressure command value F_thw. I can. However, because of the turning state, the first threshold value THW^*In order to avoid contact with the preceding vehicle, the contact avoidance control intervention is performed at a shorter inter-vehicle distance than when no such correction is made. The braking deceleration of the vehicle becomes large, and the driver feels uncomfortable.
[0061]
Therefore, the contact avoidance control is performed with the second brake fluid pressure command value F_ttc in which the control gain G_ttc is changed according to the turning state before the contact avoidance control intervenes at such a short inter-vehicle distance. Thus, it is possible to prevent the driver from feeling uncomfortable.
As described above, in the turning state, the first threshold value THW^*And the control gain G_ttc, and various effects can be obtained by selectively determining the brake fluid pressure command value based on the first contact possibility index THW and the second contact possibility index TTC. .
[0062]
The effect of selectively determining the brake fluid pressure command value based on the first contact possibility index THW and the second contact possibility index TTC is, for example, as follows.
As described above, it is determined whether or not the first brake fluid pressure command value F_thw is smaller than the second brake fluid pressure command value F_ttc (F_thw <F_ttc) by the processing of step S7 to step S9 in FIG. When the first brake fluid pressure command value F_thw is smaller than the second brake fluid pressure command value F_ttc, the final brake fluid pressure command value F is set as the first brake fluid pressure command value F_thw (F = F_thw), When the first brake fluid pressure command value F_thw is equal to or greater than the second brake fluid pressure command value F_ttc, the final brake fluid pressure command value F is set as the second brake fluid pressure command value F_ttc (F = F_ttc).
[0063]
  As described above, the first contact possibility index THW and the second contact possibility indexContactability indexIt is significant to determine the brake fluid pressure command value based on TTC and implement contact avoidance control. However, depending on the relationship between the host vehicle and the preceding vehicle, the firstContactability indexTHW is the first threshold THW^*At the same time as the secondContactability indexAlso for THW, the second threshold TTC^*In this case, if the contact avoidance control is performed in consideration of both of these two contact possibility indexes, the control amount becomes too large and the drivability may be impaired.
[0064]
For this reason, contact avoidance control without impairing drivability can be realized by performing contact avoidance control in a direction in which the host vehicle is safe based on one of the contact possibility indexes.
The embodiment of the present invention has been described above. However, the present invention is not limited to being realized as the above-described embodiment.
[0065]
That is, in the above-described embodiment, as described with reference to FIG. 4, the first threshold value THW^*Is obtained in relation to the amount of change in rudder angle, but is not limited to this. FIG. 11 shows such another example, and the vertical axis represents the first threshold value THW.^*And the horizontal axis represents the amount of lateral displacement (lateral relative distance), and the first threshold value THW for the amount of lateral displacement.^*The characteristic figure of is shown. For example, the lateral displacement amount is a relative distance in the lateral direction detected by the radar 1 and is a value obtained by the calculation unit 13 as shown in FIG. As shown in FIG. 11, as the lateral displacement amount increases, the first threshold value THW^*Decreases after a certain lateral displacement amount, the first threshold THW^*Becomes a constant characteristic. Based on such a characteristic diagram, the first threshold THW corresponding to the lateral displacement amount^*To decide.
[0066]
As described above, the first threshold value THW according to the amount of lateral displacement at the time of lane change.^*By determining, the intervention timing of the contact avoidance control can be changed according to the lateral displacement amount at the time of lane change. That is, the greater the lateral displacement amount (the greater the lateral relative distance), the first threshold THW.^*As a result, the intervention timing of the contact avoidance control can be delayed as the lateral displacement amount increases.
[0067]
Further, the first threshold value THW increases as the lateral displacement increases.^*In the region where the decrease occurs, the inclination may be changed according to the vehicle width of the preceding vehicle. Specifically, when the vehicle width of the preceding vehicle is wide, the inclination is reduced, that is, the first threshold value THW for the lateral displacement amount.^*When the vehicle width of the preceding vehicle is small, the inclination is increased, that is, the first threshold value THW for the lateral displacement amount is reduced.^*Increase the amount of change.
[0068]
For example, the lateral displacement amount decreases as the vehicle width of the preceding vehicle decreases. This is because in the lane change, if the vehicle width of the preceding vehicle is narrow, the amount of avoidance in the lateral direction is reduced. For this reason, when the vehicle width of the preceding vehicle is narrow, the first contact possibility index THW is the first threshold value THW.^*The intervention timing of the contact avoidance control can be made later.
[0069]
Furthermore, FIG. 12 is another example, and the vertical axis represents the first threshold value THW.^*And the horizontal axis represents the blinker operation elapsed time, and the first threshold value THW for the blinker operation elapsed time.^*The characteristic figure of is shown. For example, the blinker operation elapsed time is the elapsed time from the start of the blinker operation detected from the operation state of the blinker changeover switch 6, and is a value obtained by the calculation unit 13 as shown in FIG. As shown in FIG. 12, as the blinker operation elapsed time passes, the first threshold THW^*Decreases after a certain blinker operation elapsed time, the first threshold THW^*Becomes a constant characteristic (characteristic indicated by a solid line). Based on such a characteristic diagram, the first threshold THW corresponding to the blinker operation elapsed time^*To decide.
[0070]
Thus, the first threshold value THW according to the blinker operation elapsed time^*By determining the lane change, it is possible to predict the lane change and change the intervention timing of the contact avoidance control according to the blinker operation elapsed time. That is, as the turn signal operation elapsed time passes, the first threshold THW^*As a result, the intervention timing of the contact avoidance control can be delayed more as the turn signal operation elapsed time is longer.
[0071]
Further, when the blinker operation elapsed time reaches a certain time, the first threshold value THW^*May be increased (characteristics indicated by broken lines). In some cases, the driver hesitates to change lanes and travels straight with the turn signal on. In such a case, the first threshold THW^*And the intervention timing of the contact avoidance control can be changed.
[0072]
In the above-described embodiment, as described with reference to FIG. 5, the control gain G_ttc is obtained in relation to the amount of change in the steering angle, but the present invention is not limited to this.
FIG. 13 shows such another example, in which the vertical axis represents the control gain G_ttc, the horizontal axis represents the above-mentioned lateral displacement amount (lateral relative distance), and the first threshold value THW for the lateral displacement amount.^*The characteristic figure of is shown. As shown in FIG. 13, the control gain G_ttc increases as the lateral displacement amount increases, and the control gain G_ttc becomes constant after a certain lateral displacement amount. Based on such a characteristic diagram, a control gain G_ttc corresponding to the lateral displacement amount is determined.
[0073]
In the region where the control gain G_ttc increases as the lateral displacement increases, the inclination may be changed according to the vehicle width of the preceding vehicle. Specifically, when the vehicle width of the preceding vehicle is narrow, the inclination is increased, that is, the amount of change in the control gain G_ttc with respect to the lateral displacement is increased, and when the vehicle width of the preceding vehicle is wide, the inclination is decreased, that is, The change amount of the control gain G_ttc with respect to the displacement amount is reduced.
[0074]
Further, FIG. 14 shows another example, in which the vertical axis represents the control gain G_ttc, the horizontal axis represents the aforementioned blinker operation elapsed time, and a characteristic diagram of the control gain G_ttc with respect to the blinker operation elapsed time. As shown in FIG. 14, the control gain G_ttc increases as the blinker operation elapsed time elapses, and the control gain G_ttc becomes constant after a certain blinker operation elapsed time (characteristic indicated by a solid line). Based on such a characteristic diagram, the control gain G_ttc corresponding to the blinker operation elapsed time is determined. It should be noted that the control gain G_ may be decreased when the blinker operation elapsed time reaches a certain time (characteristic indicated by a broken line).
[Brief description of the drawings]
FIG. 1 is a diagram showing a vehicle travel safety support apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a controller provided in the travel safety support apparatus.
FIG. 3 is a flowchart showing a processing procedure of the control controller.
FIG. 4 is a characteristic diagram used for obtaining a first threshold value from a steering angle change amount;
FIG. 5 is a characteristic diagram used for obtaining a control gain from a steering angle change amount;
FIG. 6 is a diagram used for explaining the contact avoidance control by the first contact possibility index THW.
FIG. 7 is a diagram used for explaining contact avoidance control based on a second contact possibility index TTC.
FIG. 8 is a diagram used for explaining the contact avoidance control by the first contact possibility index THW when the vehicle is in a turning state.
FIG. 9 is a comparative example with FIG. 8 in which the first threshold is fixed, and is a diagram used for explaining the contact avoidance control by the first contact possibility index THW when the vehicle is in a turning state.
FIG. 10 is a diagram used for explaining the contact avoidance control by the second contact possibility index TTC when the vehicle is in a turning state.
FIG. 11 is a characteristic diagram used for obtaining a first threshold value from a lateral displacement amount;
FIG. 12 is a characteristic diagram used to obtain the first threshold value from the blinker operation elapsed time.
FIG. 13 is a characteristic diagram used to obtain a control gain from a lateral displacement amount.
FIG. 14 is a characteristic diagram used to obtain a control gain from the blinker operation elapsed time.
[Explanation of symbols]
1 Radar
2 Rudder angle sensor
3 Wheel speed sensor
4 Steering wheel
5 wheels
6 Winker selector switch
7 Brake control unit
8 Braking device
10 Control controller
11 1st contact possibility parameter | index calculation part
12 Second contact possibility index calculation unit
13 Calculation unit
101 Own vehicle
102 preceding vehicle

Claims (1)

In a driving safety support device that operates braking control that avoids vehicle contact with an object at a predetermined timing,
The first contact possibility index obtained by dividing the relative distance between the vehicle and the object in front of the vehicle by the vehicle speed of the vehicle is set according to the first contact possibility index. If below a value, it performs the brake control, or the second contact possibility index the relative distance obtained by dividing a relative speed between the vehicle and the object to an object in front of the vehicle and the vehicle is A braking control means for performing the braking control when it falls below a threshold value set corresponding to the second contact possibility index, and selectively performing the two braking controls;
When the vehicle is in Orbiting state, while changing a threshold value set in correspondence with the first contact probability index, before Symbol second contact probability index is the second contact possibility Changing means for changing the control gain of the braking control to be performed when it falls below the threshold value set corresponding to the index ,
The control gain increases the braking force of the braking control as the value increases.
The change means decreases the threshold set corresponding to the first contact possibility index and increases the rudder angle change amount indicating the turning state of the vehicle, and also indicates the turning state of the vehicle. The travel safety support device , wherein the control gain is increased as the amount of change in angle increases .

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