JP2016126369A - Control system of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system of a vehicle capable of reliably avoiding collision with a forward obstacle without giving a driver a strange feeling.SOLUTION: A control system of a vehicle includes a forward sensor (4) that detects a distance from an own vehicle (1) to a forward obstacle and a relative speed of the own vehicle with respect to the forward obstacle, and a control unit (24) that acquires a steering avoidable distance, which is the shortest distance to the forward obstacle at which collision with the forward obstacle can be avoided merely by steering the own vehicle, and a braking avoidable distance, which is the shortest distance to the forward obstacle at which collision with the forward obstacle can be avoided merely by braking the own vehicle, on the basis of the relative speed of the own vehicle with respect to the forward obstacle, and that, when the distance between the braking avoidable distance and steering avoidable distance falls below a predetermined value and the distance from the own vehicle to the forward obstacle is equal to or smaller than the steering avoidable distance or braking avoidable distance, if a driver's steering intension is not detected, restricts steering of the own vehicle using a steering actuator (18) and decelerates the own vehicle using a brake (28).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a vehicle control device, and more particularly, to a vehicle control device that controls the host vehicle so as to avoid a collision with a front obstacle existing in front of the host vehicle.

2. Description of the Related Art Conventionally, there has been known a vehicle control device that avoids a collision with a front obstacle by operating an automatic brake when the presence of a front obstacle present in front of the host vehicle is detected. In addition, a technique for suppressing interference between the automatic brake and the driver's operation has been proposed.
For example, in Patent Document 1, a driver's avoidance action for an object that is a threat to the host vehicle is determined, and the collision between the driver's operation and the automatic brake control system is suppressed and the collision is caused by the intervention of the automatic brake control system. An avoidance operation determination device that aims to avoid and reduce collision is disclosed.

JP 2014-008931 A

  By the way, the shortest distance between the front obstacle and the own vehicle that can avoid a collision with the front obstacle only by the brake of the own vehicle (the braking avoidable distance) is an index as the relative speed of the own vehicle with respect to the front obstacle increases. It increases functionally. On the other hand, the shortest distance between the front obstacle and the host vehicle that can avoid a collision with the front obstacle only by steering the host vehicle (steering avoidable distance) is linear as the relative speed of the host vehicle with respect to the front obstacle increases. Increase. Depending on the relative speed, there are cases where the steering avoidable distance is longer than the braking avoidable distance and vice versa.

For example, when the distance from the host vehicle to the front obstacle is shorter than the steerable avoidance distance but longer than the brake avoidable distance, the host vehicle is sufficiently in front of the front obstacle by operating the automatic brake of the host vehicle. It is possible to avoid the collision with the front obstacle.
If the distance from the host vehicle to the front obstacle is shorter than the braking avoidable distance but longer than the steering avoidable distance, the driver performs the steering operation to sufficiently move the host vehicle in the left-right direction of the front obstacle. It can be moved to avoid collisions with front obstacles.

However, in the conventional apparatus as described above, the steering avoidable distance and the brake avoidable distance are not considered.
Therefore, for example, when the distance from the host vehicle to the front obstacle is shorter than the steering avoidable distance but longer than the brake avoidable distance, the driver may perform the steering operation together with the operation of the automatic brake. In this case, a part of the frictional force generated between the tire and the road surface is used as a cornering force, and the maximum braking force that can be generated by automatic braking is reduced accordingly. There may be a situation where the vehicle cannot be sufficiently decelerated, and the distance from the host vehicle to the front obstacle is shorter than the steerable avoidance distance, and the host vehicle cannot be sufficiently moved in the left-right direction of the front obstacle. .
In addition, when the distance from the host vehicle to the obstacle ahead is shorter than the steering avoidable distance but longer than the brake avoidable distance, there is a possibility that the automatic brake may be activated together with the driver's steering operation. This makes the driver trying to avoid a collision with a forward obstacle feel uncomfortable and annoying.

  The present invention has been made to solve the above-described problems of the prior art, and can reliably avoid a collision with a front obstacle without causing the driver to feel uncomfortable. The purpose is to provide.

In order to achieve the above object, a vehicle control device according to the present invention is a vehicle control device that controls a host vehicle so as to avoid a collision with a front obstacle existing ahead of the host vehicle. Brake control means for controlling the braking of the vehicle, steering control means for controlling the steering of the host vehicle, the distance from the host vehicle to the front obstacle, and the front obstacle for detecting the relative speed of the host vehicle with respect to the front obstacle Based on the detection means, the steering intention detection means for detecting the steering intention of the host vehicle by the driver, and the relative speed of the host vehicle with respect to the front obstacle detected by the front obstacle detection means, a collision with the front obstacle is detected. Steering avoidable distance acquisition means for acquiring a steering avoidable distance that is the shortest distance between the front obstacle and the own vehicle that can be avoided only by steering, and the own vehicle with respect to the forward obstacle detected by the forward obstacle detecting means phase Brake avoidable distance acquisition means for acquiring a brake avoidable distance that is the shortest distance between the front obstacle and the host vehicle, which can avoid a collision with a front obstacle only by braking the host vehicle based on the speed, and can avoid braking The difference between the distance and the steering avoidable distance is less than a predetermined value, and the distance from the host vehicle to the front obstacle detected by the front obstacle detecting means is equal to or less than the steering avoidable distance or the braking avoidable distance. And a collision avoidance control means for restricting the steering of the host vehicle by the steering control means and decelerating the host vehicle by the braking control means when the driver's intention to steer the host vehicle is not detected.
In the present invention configured as described above, the collision avoidance control means includes a difference between the braking avoidable distance and the steering avoidable distance that is less than a predetermined value and is detected from the own vehicle detected by the forward obstacle detecting means. When the distance to the front obstacle is equal to or less than the steering avoidable distance or the braking avoidable distance, and if the driver does not detect the steering intention of the own vehicle, the steering control means restricts the steering of the own vehicle and the braking control means Since the host vehicle is decelerated by the vehicle, braking and steering of the host vehicle are prevented from being performed simultaneously in a situation where there is no room for avoiding a collision with a front obstacle by either braking or steering of the host vehicle. The frictional force generated between the vehicle and the road surface can be used effectively as a braking force, which makes the driver who does not intend to steer the vehicle feel uncomfortable. It is possible to reliably avoid the collision with the front obstacle by the braking of the vehicle without.

In the present invention, it is preferable that the collision avoidance control unit has a difference between the braking avoidable distance and the steering avoidable distance that is less than a predetermined value, and the front obstacle is detected from the own vehicle detected by the front obstacle detecting unit. When the driver's intention to steer the vehicle is detected when the distance to the object is equal to or less than the steering avoidable distance or the braking avoidable distance, the braking control means restricts the braking of the own vehicle and the steering control means Allow the vehicle to steer.
In the present invention configured as described above, the collision avoidance control means can simultaneously perform braking and steering of the host vehicle in a situation where there is no room for avoiding a collision with a front obstacle by either braking or steering of the host vehicle. The frictional force generated between the tire and the road surface can be effectively used as a cornering force, so that the driver who intends to steer the vehicle does not feel uncomfortable. A collision with a forward obstacle can be reliably avoided by steering the host vehicle.

In the present invention, it is preferable that the vehicle control device further includes a rear side vehicle detecting unit that detects a rear side vehicle that travels in the rear side of the host vehicle, and the collision avoidance control unit includes the braking unit. The difference between the avoidable distance and the steering avoidable distance is less than a predetermined value, and the distance from the host vehicle to the front obstacle detected by the front obstacle detecting means is less than the steering avoidable distance or the braking avoidable distance. In some cases, when the rear side vehicle is detected by the rear side vehicle detection means, the steering control means restricts the steering of the own vehicle regardless of whether the driver's intention to steer the vehicle is detected. Then, the host vehicle is decelerated by the braking control means.
In the present invention configured as described above, the collision avoidance control means is operated by the rear side vehicle detection means in a situation where there is no room for avoiding a collision with a front obstacle by either braking or steering of the host vehicle. When a side vehicle is detected, the steering of the host vehicle is restricted and the host vehicle is decelerated. Therefore, the host vehicle is sufficiently decelerated by effectively using the frictional force generated between the tire and the road surface as a braking force. As a result, even when the rear vehicle approaches the side of the host vehicle and the host vehicle cannot perform steering to avoid a collision with the front obstacle, A collision can be reliably avoided by braking the host vehicle.

In the present invention, it is preferable that the steering control means applies an assist torque corresponding to the driver's steering operation to the steering mechanism of the host vehicle.
In the present invention configured as described above, the steering is performed so as to assist the steering operation of the driver, so that the driver who intends to steer the own vehicle does not feel a sense of incongruity and does not collide with a front obstacle. This can be avoided reliably by steering the host vehicle.

  According to the vehicle control apparatus of the present invention, it is possible to reliably avoid a collision with a front obstacle without making the driver feel uncomfortable.

It is the diagram which showed the relationship between the distance required in order to avoid the collision with a front obstacle, and the relative speed of the own vehicle with respect to a front obstacle. 5 is a schematic plan view illustrating the positional relationship between a braking avoidable distance and a steering avoidable distance. FIG. 5 is a schematic plan view illustrating the positional relationship between a braking avoidable distance and a steering avoidable distance. FIG. FIG. 5 is a diagram showing the relationship between braking deceleration and the distance necessary to avoid a collision with a front obstacle when the maximum frictional force generated between a tire and a road surface is distributed to a braking force and a cornering force. . 1 is a schematic plan view of a vehicle equipped with a control device according to an embodiment of the present invention. It is a block diagram which shows the electric constitution of the vehicle carrying the control apparatus by embodiment of this invention. It is a flowchart of the collision avoidance control which the vehicle control apparatus by embodiment of this invention performs. It is a flowchart of the 1st collision avoidance process in the collision avoidance control of FIG. It is a flowchart of the 2nd collision avoidance process in the collision avoidance control of FIG. It is a flowchart of the 3rd collision avoidance process in the collision avoidance control of FIG.

Hereinafter, a vehicle control apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the relationship between the distance required to avoid a collision with a front obstacle and the relative speed of the host vehicle with respect to the front obstacle will be described with reference to FIGS. FIG. 1 is a diagram showing the relationship between the distance required to avoid a collision with a front obstacle and the relative speed of the host vehicle with respect to the front obstacle, and FIGS. It is the schematic plan view which illustrated the positional relationship of the possible distance and the steering avoidable distance.

  In FIG. 1, the horizontal axis represents the relative speed Vr of the host vehicle with respect to the front obstacle, and the vertical axis represents the distance from the front obstacle necessary for avoiding a collision with the front obstacle. In addition, “avoidance of collision with a front obstacle” refers to the relative speed of the own vehicle with respect to the front obstacle before the distance from the own vehicle to the front obstacle becomes zero in the case of avoidance by braking of the own vehicle. In the case of avoidance by steering the host vehicle, the host vehicle moves in the vehicle width direction to a position where the vehicle body and the front obstacle of the host vehicle do not overlap at all in the vehicle width direction. Means.

As shown in FIG. 1, the shortest distance (braking avoidable distance) Lb between the front obstacle and the own vehicle that can avoid a collision with the front obstacle only by braking the own vehicle is As the relative velocity Vr increases, it increases exponentially. On the other hand, the shortest distance (steering avoidable distance) Ls between the front obstacle and the host vehicle that can avoid a collision with the front obstacle only by steering the host vehicle increases the relative speed Vr of the host vehicle with respect to the front obstacle. Linearly increases as
In particular, when the relative speed Vr of the host vehicle with respect to the front obstacle is less than the predetermined speed Ve, the steering avoidable distance Ls is longer than the braking avoidable distance Lb, and the relative speed Vr of the host vehicle with respect to the front obstacle is the predetermined speed. When larger than Ve, the steering avoidable distance Ls is shorter than the brake avoidable distance Lb.
Here, the speed Ve is a boundary speed at which the magnitude of the steering avoidable distance Ls and the brake avoidable distance Lb is switched, and is determined using the vehicle weight, tire performance, brake performance, road surface μ, and the like as parameters. In the present embodiment, the boundary velocity Ve is 40 km / h, for example.

That is, when the relative speed Vr of the host vehicle with respect to the front obstacle is less than the boundary speed Ve, as shown in FIG. 2, the steering avoidable distance Ls is longer than the braking avoidable distance Lb.
For example, in a region where the distance Lo from the host vehicle to the front obstacle is equal to or greater than the steering avoidable distance Ls, a collision with the front obstacle can be avoided by either steering or braking.
Further, when the host vehicle approaches a front obstacle up to a region satisfying Lb ≦ Lo <Ls, a collision with the front obstacle cannot be avoided only by steering the host vehicle, but a collision with the front obstacle is braked by the host vehicle. It can only be avoided.
Further, when the host vehicle approaches the front obstacle and enters the region of Lo <Lb, the collision with the front obstacle cannot be avoided even by braking the host vehicle.

On the other hand, when the relative speed Vr of the host vehicle with respect to the front obstacle is larger than the boundary speed Ve, the steering avoidable distance Ls is shorter than the brake avoidable distance Lb as shown in FIG.
For example, in a region where the distance Lo from the host vehicle to the front obstacle is equal to or greater than the steering avoidable distance Lb, a collision with the front obstacle can be avoided by either steering or braking.
Further, when the host vehicle approaches a front obstacle up to a region satisfying Ls ≦ Lo <Lb, a collision with the front obstacle cannot be avoided only by braking the host vehicle, but a collision with the front obstacle is steered by the host vehicle. It can only be avoided.
Further, when the host vehicle approaches the front obstacle and enters the region of Lo <Ls, the collision with the front obstacle cannot be avoided even by steering the host vehicle.

  Next, referring to FIG. 4, the distance necessary for avoiding a collision with a front obstacle when the steering and braking of the host vehicle are combined will be described. FIG. 4 shows the relationship between the braking deceleration and the distance required to avoid a collision with a front obstacle when the maximum frictional force generated between the tire and the road surface is distributed to the braking force and the cornering force. FIG. The “distance necessary for avoiding a collision with a front obstacle” in FIG. 4 is a condition where the combined force of the braking force generated by braking and the cornering force generated by steering is a predetermined road surface μ (for example, 0.9). The steering angle is determined according to the braking deceleration so as to be equal to the maximum friction force that can be generated between the tire and the road surface, and is a distance estimated based on the braking deceleration and the steering angle. In FIG. 4, the horizontal axis represents the deceleration D due to braking to avoid a collision with the front obstacle, and the vertical axis represents the distance from the front obstacle necessary for avoiding the collision with the front obstacle. ing.

As shown in FIG. 4, in the range where the relative speed Vr of the host vehicle with respect to the front obstacle is equal to or less than the boundary speed Ve, the greater the braking deceleration D, the greater the distance from the front obstacle necessary for avoiding the collision with the front obstacle. When the distance (avoidable distance) L is short and the braking deceleration D is 0 (that is, when a collision with a front obstacle is avoided only by steering the host vehicle), the avoidable distance L becomes the maximum value, When the braking deceleration D is the maximum deceleration Dmax (for example, 9 m / s ² ) (that is, when the collision with the front obstacle is avoided only by braking the host vehicle), the avoidable distance L is the minimum value.
When the relative speed Vr of the host vehicle with respect to the front obstacle is equal to the boundary speed Ve, the avoidable distance L is substantially constant regardless of the braking deceleration D.
Further, in the range where the relative speed Vr of the host vehicle with respect to the front obstacle is larger than the boundary speed Ve, the avoidable distance L becomes longer as the braking deceleration D becomes larger. More specifically, the avoidable distance L is substantially constant in the range of the braking deceleration D up to a braking deceleration (intermediate deceleration) Dmid (for example, 5 m / s ² ) that is 70% or less of the maximum deceleration Dmax. When the deceleration D becomes larger than the intermediate deceleration Dmid, the avoidable distance L increases exponentially as the braking deceleration D increases.

  Next, a vehicle equipped with a control device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a schematic plan view of a vehicle equipped with a control device according to an embodiment of the present invention, and FIG. 6 is a block diagram showing an electrical configuration of the vehicle equipped with a control device according to an embodiment of the present invention.

As shown in FIG. 5, the code | symbol 1 shows the vehicle carrying the vehicle control apparatus by this embodiment. The vehicle 1 includes a front camera 2 that captures the front of the vehicle 1, a front sensor 4 that detects an obstacle ahead of the vehicle 1, and another vehicle that travels on the rear side of the vehicle 1 (hereinafter referred to as “rear side vehicle”). A rear side sensor 6 that detects the sight of the passenger, a pedal stroke sensor 10 that detects the amount of depression of an accelerator pedal or a brake pedal, and a direction indicator that detects an operation on the direction indicator A switch 12 is provided. The front sensor 4 includes a millimeter wave radar or a laser radar that detects an object in front of the vehicle 1, and indicates the presence of a front obstacle, the distance from the own vehicle 1 to the front obstacle, and the relative speed of the own vehicle 1 with respect to the front obstacle. To detect. The rear side sensor 6 includes a millimeter wave radar or a laser radar that detects an object behind the vehicle 1, and detects the presence of the rear side vehicle and the inter-vehicle distance between the rear side vehicle and the host vehicle 1.
The vehicle 1 also has a steering actuator 18 that applies steering assist force to the steering wheel 14 and the steering shaft 16. A rack and pinion type steering gear device is connected to the steering shaft 16, and the left and right steering wheels are steered.

Further, as shown in FIG. 6, the vehicle 1 includes a vehicle speed sensor 20 that detects the vehicle speed, a steering angle sensor 22 that detects the steering angle of the steering wheel 14, and a control unit 24.
Image data captured by the front camera 2 and signals from the sensors and the direction indicator switch 12 are input to the control unit 24. The control unit 24 calculates control signals to be given to the steering actuator 18, the engine 26, and the brake 28 based on the image data input from the front camera 2 and the signals input from each sensor and the direction indicator switch 12. Perform collision avoidance control. The control unit 24 includes a CPU, various programs that are interpreted and executed on the CPU (including basic control programs such as an OS and application programs that are activated on the OS to realize specific functions), programs, and various data. Is constituted by a computer having an internal memory such as a ROM or a RAM for storing.

Next, the collision avoidance control performed by the control device of the vehicle 1 will be described with reference to FIGS.
7 is a flowchart of the collision avoidance control executed by the control device for the vehicle 1 according to the embodiment of the present invention, FIG. 8 is a flowchart of the first collision avoidance process in the collision avoidance control of FIG. 7, and FIG. FIG. 10 is a flowchart of the third collision avoidance process in the collision avoidance control of FIG. 7.

  First, the collision avoidance control process will be described with reference to FIG. The collision avoidance control process is a process for controlling the host vehicle 1 so as to avoid a collision with a front obstacle existing ahead of the host vehicle 1, and is repeatedly executed after the ignition switch of the vehicle 1 is turned on. The

  When the collision avoidance control process is started, in step S1, the control unit 24 determines whether or not a front obstacle is detected by the front camera 2 or the front sensor 4. As a result, when a front obstacle is not detected, this step S1 is repeated.

  On the other hand, when a front obstacle is detected by the front camera 2 or the front sensor 4, the process proceeds to step S2, and the control unit 24 is based on the image data photographed by the front camera 2 or the signal input from the front sensor 4. A distance Lo from the host vehicle 1 to the front obstacle and a relative speed Vr of the host vehicle 1 with respect to the front obstacle are specified.

  Next, in step S3, the control unit 24 determines whether or not the relative speed Vr of the host vehicle 1 with respect to the front obstacle specified in step S2 is greater than a value obtained by adding a predetermined value α to the boundary speed Ve (Vr> Ve + α). Or not) is determined. Here, the predetermined value α is an absolute value of a difference between the relative speed Vr and the boundary speed Ve when the difference between the steering avoidable distance Ls and the brake avoidable distance Lb is less than a predetermined value β (for example, 1 m). For example, α = 1 km / h.

As a result, when Vr> Ve + α is satisfied, the process proceeds to step S4, and the control unit 24 executes the first collision avoidance process.
In this case, since the relative speed Vr of the host vehicle 1 with respect to the front obstacle is larger than the boundary speed Ve, as shown in FIGS. 1 and 3, the steering avoidable distance Ls is shorter than the braking avoidable distance Lb. .

  On the other hand, if Vr> Ve + α is not satisfied (Vr ≦ Ve + α), the process proceeds to step S5, and the control unit 24 determines that the relative speed Vr of the host vehicle 1 with respect to the front obstacle specified in step S2 is predetermined from the boundary speed Ve. It is determined whether or not the value α is larger than the value obtained by subtraction (whether or not Ve + α ≧ Vr> Ve−α is satisfied).

As a result, when Ve + α ≧ Vr> Ve−α is satisfied, the process proceeds to step S6, and the control unit 24 executes a second collision avoidance process.
In this case, the difference between the steering avoidable distance Ls and the brake avoidable distance Lb is less than the predetermined value β, and the steering avoidable distance Ls and the brake avoidable distance Lb are substantially equal.

On the other hand, when Ve + α ≧ Vr> Ve−α is not satisfied (Vr <Ve−α), the process proceeds to step S7, and the control unit 24 executes the third collision avoidance process.
In this case, since the relative speed Vr of the host vehicle 1 with respect to the front obstacle is smaller than the boundary speed Ve, as shown in FIGS. 1 and 2, the steering avoidable distance Ls is longer than the brake avoidable distance Lb. .

  After executing the first collision avoidance process, the second collision avoidance process, or the third collision avoidance process, the control unit 24 ends the collision avoidance control process.

  Next, the first collision avoidance process will be described with reference to FIG. This first collision avoidance process is a process for performing collision avoidance control when the steering avoidable distance Ls is shorter than the brake avoidable distance Lb, as described above.

  As shown in FIG. 8, when the first collision avoidance process is started, in step S10, the control unit 24 determines that the distance Lo from the vehicle 1 specified in step S2 of FIG. It is determined whether or not it is less than the possible distance Lb. For example, a map indicating the relationship between the relative speed Vr of the host vehicle 1 with respect to a front obstacle as shown in FIG. 1 and the braking avoidable distance Lb is stored in the memory of the control unit 24 in advance, With reference to the map, a brake avoidable distance Lb corresponding to the relative speed Vr of the host vehicle 1 with respect to the front obstacle specified in step S2 of FIG. 7 is acquired, and the distance Lo from the host vehicle 1 to the front obstacle is obtained. Then, it is determined whether or not the braking avoidable distance Lb is less than or equal to.

  As a result, when the distance Lo from the host vehicle 1 to the front obstacle is not less than the braking avoidable distance Lb (longer than the braking avoidable distance Lb), it is still necessary to perform control for avoiding a collision with the front obstacle. The control unit 24 ends the first collision avoidance process and returns to the main routine.

On the other hand, if the distance Lo from the host vehicle 1 to the front obstacle is shorter than the braking avoidable distance Lb, the process proceeds to step S11, and the control unit 24 determines whether or not the rear side vehicle is detected by the rear side sensor 6. Determine.
As a result, when the rear side vehicle is detected by the rear side sensor 6, the rear side vehicle approaches the side of the own vehicle 1 so that the own vehicle 1 avoids a collision with a front obstacle. The control unit 24 proceeds to step S12, and the control unit 24 controls the brake 28 so as to decelerate the host vehicle 1 at the maximum deceleration Dmax, and is generated between the tire and the road surface. In order to effectively use the frictional force as the braking force, the steering of the host vehicle 1 is limited. When limiting the steering of the host vehicle 1, the control unit 24 steers torque in a direction that cancels the steering force of the driver so that the steering torque is not applied to the steering shaft 16 even when the driver operates the steering wheel 14. It is generated by the actuator 18.

  Then, the control unit 24 continues the deceleration at the maximum speed Dmax until it is determined in step S13 that the collision with the front obstacle has been avoided. When it is determined in step S13 that the collision with the front obstacle is avoided, that is, before the distance from the own vehicle 1 to the front obstacle becomes zero, the relative speed of the own vehicle 1 with respect to the front obstacle becomes 0 or less. If this happens, the control unit 24 ends the first collision avoidance process and returns to the main routine.

On the other hand, if no rear side vehicle is detected by the rear side sensor 6 in step S11, the process proceeds to step S14, and the control unit 24 starts from the occupant sensor 8, the steering angle sensor 22, and the direction indicator switch 12. Based on the output signal, it is determined whether or not the driver intends to steer the vehicle 1.
For example, when the control unit 24 determines that the occupant has recognized a front obstacle based on the sight line of the occupant detected by the occupant sensor 8, or when the steering operation is detected by the steering angle sensor 22, or When the operation of the direction indicator is detected by the direction indicator switch 12, it is determined that the steering intention of the host vehicle 1 by the driver has been detected.

  As a result, when the steering intention of the host vehicle 1 by the driver is not detected, the process proceeds to step S12, and the control unit 24 uses the host vehicle 1 only to brake the host vehicle 1 in order to avoid a collision with a front obstacle. The brake 28 is controlled to decelerate at the maximum deceleration Dmax.

On the other hand, if the driver's intention to steer the host vehicle 1 is detected in step S14, the process proceeds to step S15, and the control unit 24 prioritizes the driver's steering intention and needs to avoid a collision with a front obstacle. In order to decelerate the host vehicle 1 with a deceleration that does not affect the avoidable distance L, the brake 28 is controlled to decelerate the host vehicle 1 with an intermediate deceleration Dmid (for example, 5 m / s ² ). The steering of the host vehicle 1 by the driver's steering operation is allowed.
As described above with reference to FIG. 4, when the relative speed Vr of the host vehicle 1 with respect to the front obstacle is larger than the boundary speed Ve (that is, the steering avoidable distance Ls is shorter than the brake avoidable distance Lb), the braking deceleration is achieved. The avoidable distance L is substantially constant when D is in the range from 0 to the intermediate deceleration Dmid. Therefore, the control unit 24 controls the brake 28 so as to decelerate the host vehicle 1 at the intermediate deceleration Dmid in step S15, and allows the driver to steer the host vehicle 1 by the steering operation of the driver. The host vehicle 1 can be decelerated without affecting forward obstacle avoidance, and collision with the forward obstacle can be avoided more reliably.

And it progresses to step S16 and the control unit 24 determines whether the collision to a front obstruction was avoided.
As a result, when it is determined that the collision with the front obstacle is avoided, that is, before the distance from the own vehicle 1 to the front obstacle becomes zero, the relative speed of the own vehicle 1 with respect to the front obstacle becomes 0 or less. If this happens, the control unit 24 ends the first collision avoidance process and returns to the main routine.

  On the other hand, if it is determined in step S16 that the collision with the front obstacle is not avoided, the process proceeds to step S17, and the control unit 24 determines that the distance Lo from the host vehicle 1 to the front obstacle is the steering avoidable distance Ls. It is determined whether or not. For example, a map showing the relationship between the relative speed Vr of the host vehicle 1 with respect to the obstacle ahead and the steering avoidable distance Ls as shown in FIG. 1 is stored in the memory of the control unit 24 in advance, With reference to the map, the steering avoidable distance Ls corresponding to the relative speed Vr of the host vehicle 1 with respect to the front obstacle specified in step S2 of FIG. 7 is acquired, and the distance Lo from the host vehicle 1 to the front obstacle is obtained. Then, it is determined whether the steering avoidable distance Ls or less.

  As a result, if the distance Lo from the host vehicle 1 to the front obstacle is not less than the steering avoidable distance Ls (Lo is longer than Ls), it is assumed that there is still a margin before steering avoidance is started, step S15. Return to. Thereafter, until it is determined in step S16 that the collision with the front obstacle has been avoided, or until the distance Lo from the host vehicle 1 to the front obstacle becomes equal to or less than the steering avoidable distance Ls in step S17, the intermediate deceleration in step S15. The deceleration by Dmid and the permission of the steering of the host vehicle 1 are continued.

  In step S17, when the distance Lo from the host vehicle 1 to the front obstacle becomes equal to or less than the steering avoidable distance Ls, the process proceeds to step S18, and the control unit 24 collides with the front obstacle by the steering of the host vehicle 1. Steering assist is performed to avoid the problem. Specifically, the control unit 24 determines the own vehicle 1 to avoid a collision with the front obstacle based on the distance Lo from the own vehicle 1 to the front obstacle and the relative speed Vr of the own vehicle 1 with respect to the front obstacle. The steering actuator 18 is controlled so that the steering torque necessary for realizing the yaw rate is applied to the steering shaft 16.

  Then, the control unit 24 continues the steering assist until it is determined in step S19 that the collision with the front obstacle has been avoided. When it is determined in step S19 that a collision with a front obstacle has been avoided, that is, when the host vehicle 1 has moved in the vehicle width direction to a position where the vehicle body of the host vehicle 1 and the front obstacle do not overlap at all in the vehicle width direction. The control unit 24 ends the first collision avoidance process and returns to the main routine.

  Next, the second collision avoidance process will be described with reference to FIG. As described above, the second collision avoidance process is a process for performing the collision avoidance control when the difference between the steering avoidable distance Ls and the brake avoidable distance Lb is less than the predetermined value β.

As shown in FIG. 9, when the second collision avoidance process is started, in step S30, the control unit 24 determines that the distance Lo from the host vehicle 1 specified in step S2 of FIG. It is determined whether or not it is less than the possible distance Lb or the steering avoidable distance Ls.
As a result, when the distance Lo from the host vehicle 1 to the front obstacle is not less than the braking avoidable distance Lb or the steering avoidable distance Ls (longer than the braking avoidable distance Lb and the steering avoidable distance Ls), it is still a forward obstacle. It is assumed that control for avoiding a collision with an object is not necessary, and the control unit 24 ends the second collision avoidance process and returns to the main routine.

On the other hand, when the distance Lo from the host vehicle 1 to the front obstacle is shorter than the braking avoidable distance Lb or the steering avoidable distance Ls, the process proceeds to step S31 and the control unit 24 uses the rear side sensor 6 to detect the rear side vehicle. It is determined whether or not is detected.
As a result, when the rear side vehicle is detected by the rear side sensor 6, the rear side vehicle approaches the side of the own vehicle 1 so that the own vehicle 1 avoids a collision with a front obstacle. The control unit 24 proceeds to step S32, and the control unit 24 controls the brake 28 so as to decelerate the host vehicle 1 at the maximum deceleration Dmax, and is generated between the tire and the road surface. In order to effectively use the frictional force as the braking force, the steering of the host vehicle 1 is limited. For example, the control unit 24 causes the steering actuator 18 to generate torque in a direction that cancels the steering force of the driver so that the steering torque is not applied to the steering shaft 16 even if the driver operates the steering wheel 14.

  Then, the control unit 24 continues the deceleration and the steering limitation at the maximum speed Dmax until it is determined in step S33 that the collision with the front obstacle is avoided. When it is determined in step S33 that the collision with the front obstacle has been avoided, that is, before the distance from the own vehicle 1 to the front obstacle becomes zero, the relative speed of the own vehicle 1 with respect to the front obstacle becomes 0 or less. If this happens, the control unit 24 ends the second collision avoidance process and returns to the main routine.

  On the other hand, if the rear side vehicle 6 is not detected by the rear side sensor 6 in step S31, the process proceeds to step S34, and the control unit 24 starts from the occupant sensor 8, the steering angle sensor 22, and the direction indicator switch 12. Based on the output signal, it is determined whether or not the driver intends to steer the vehicle 1.

  As a result, when the steering intention of the host vehicle 1 by the driver is not detected, the process proceeds to step S32, and the control unit 24 uses the host vehicle 1 only to brake the host vehicle 1 in order to avoid a collision with a front obstacle. The brake 28 is controlled to decelerate at the maximum deceleration Dmax.

On the other hand, when the steering intention of the host vehicle 1 by the driver is detected in step S34, the process proceeds to step S35, and the control unit 24 gives priority to the driver's steering intention and generates the frictional force generated between the tire and the road surface. In order to use it effectively as a cornering force, the steering actuator 18 is allowed to steer the host vehicle 1 by the steering operation of the driver, and braking of the host vehicle 1 is limited. For example, the control unit 24 controls the brake 28 so that the brake 28 does not operate even when the driver operates the brake pedal.
In step S <b> 35, the control unit 24 may not only allow the steering actuator 18 to steer the host vehicle 1 but also perform steering assist in order to avoid a collision with a front obstacle due to the steering of the host vehicle 1. .

  Then, the control unit 24 continues to permit the steering of the host vehicle 1 (and steering assist) and limit the braking until it is determined in step S36 that the collision with the front obstacle has been avoided. When it is determined in step S36 that the collision with the front obstacle has been avoided, that is, when the own vehicle 1 has moved in the vehicle width direction to a position where the vehicle body of the own vehicle 1 and the front obstacle do not overlap at all in the vehicle width direction. The control unit 24 ends the second collision avoidance process and returns to the main routine.

  Next, the third collision avoidance process will be described with reference to FIG. As described above, the third collision avoidance process is a process for performing the collision avoidance control when the steering avoidable distance Ls is longer than the brake avoidable distance Lb.

As shown in FIG. 10, when the third collision avoidance process is started, in step S50, the control unit 24 determines that the distance Lo from the vehicle 1 specified in step S2 of FIG. It is determined whether or not it is less than the possible distance Ls.
When the distance Lo from the host vehicle 1 to the front obstacle is equal to or less than the steering avoidable distance Ls, a collision with the front obstacle cannot be avoided unless appropriate steering is performed, and braking and steering of the host vehicle 1 are not possible. If performed at the same time, the frictional force generated between the tire and the road surface cannot be effectively used as a braking force.
Therefore, when it is determined in step S50 that the distance Lo from the host vehicle 1 to the front obstacle is equal to or less than the steering avoidable distance Ls, the process proceeds to step S51, and the control unit 24 decelerates the host vehicle 1 at the maximum deceleration Dmax. In order to control the brake 28 so as to cause the friction force generated between the tire and the road surface to be effectively used as a braking force, the steering of the host vehicle 1 is limited.

  Then, the control unit 24 continues the deceleration and the steering limitation at the maximum speed Dmax until it is determined in step S52 that the collision with the front obstacle has been avoided. When it is determined in step S33 that the collision with the front obstacle has been avoided, that is, before the distance from the own vehicle 1 to the front obstacle becomes zero, the relative speed of the own vehicle 1 with respect to the front obstacle becomes 0 or less. If this happens, the control unit 24 ends the third collision avoidance process and returns to the main routine.

In step S50, when the distance Lo from the host vehicle 1 to the front obstacle is not less than the steering avoidable distance Ls (Lo is longer than Ls), the process proceeds to step S53, and the control unit 24 detects the rear side sensor 6 Determines whether or not a rear side vehicle has been detected.
As a result, when the rear side vehicle is detected by the rear side sensor 6, the rear side vehicle approaches the side of the own vehicle 1 so that the own vehicle 1 avoids a collision with a front obstacle. Therefore, the control unit 24 proceeds to step S54, and the control unit 24 moves the host vehicle to the rear side vehicle before the distance Lo from the host vehicle 1 to the front obstacle becomes the steering avoidable distance Ls or less. 1 so that the host vehicle 1 can be steered to avoid a collision with a front obstacle, the preceding vehicle deceleration Dp (for example, prior to avoiding a collision with a front obstacle) The brake 28 is controlled to decelerate at 3 m / s ² ). After step S54, the control unit 24 ends the third collision avoidance process and returns to the main routine.

  In step S53, if no rear side vehicle is detected by the rear side sensor 6, control for avoiding a collision with a front obstacle is not yet required, and the control unit 24 avoids the third collision. End the process and return to the main routine.

Next, further modifications of the embodiment of the present invention will be described.
In the above-described embodiment, the vehicle 1 equipped with the vehicle control device according to the embodiment of the present invention has been described as an example in which an internal combustion engine 26 such as a gasoline engine or a diesel engine is mounted as a power source. Instead of the engine 26 or together with the engine 26, a battery and a motor may be mounted on the vehicle 1 as a power source. In this case, the control unit 24 controls the motor 1 and the brake 28 of the vehicle 1 when braking the host vehicle 1.

  In the above-described embodiment, the control unit 24 has been described as allowing or assisting the steering of the host vehicle 1, but completely controls the steering of the host vehicle 1 in order to avoid a collision with a front obstacle. You may do it.

  Next, effects of the control device for the vehicle 1 according to the above-described embodiment of the present invention and the modification of the embodiment of the present invention will be described.

  First, the control unit 24 is capable of avoiding steering by the distance Lo from the host vehicle 1 to the front obstacle detected by the front camera 2 or the front sensor 4 when the braking avoidable distance Lb is shorter than the steering avoidable distance Ls. When the distance is equal to or shorter than the distance Ls, the steering actuator 18 restricts the steering of the host vehicle 1 and the brake 28 decelerates the host vehicle 1, so that a collision with a front obstacle cannot be avoided by the steering of the host vehicle 1. Regardless of this, it is possible to prevent the vehicle 1 from being steered together with braking, and to effectively use the frictional force generated between the tire and the road surface as a braking force. It can be avoided reliably.

  Further, the control unit 24 determines that the braking avoidable distance Lb is shorter than the steering avoidable distance Ls, and the distance Lo from the host vehicle 1 to the front obstacle detected by the front camera 2 or the front sensor 4 is the steering avoidable distance Ls. In the following cases, when the rear side vehicle is detected by the rear side sensor 6, the host vehicle 1 is decelerated by the brake 28, so the distance Lo from the host vehicle 1 to the front obstacle is the steering avoidable distance Ls. Before the following, the rear vehicle can overtake the host vehicle 1 so that the host vehicle 1 can perform steering for avoiding a collision with the front obstacle. Collisions can be avoided more reliably.

  In addition, the control unit 24 determines that the difference between the braking avoidable distance Lb and the steering avoidable distance Ls is less than the predetermined value β, and the vehicle 1 to the front obstacle detected by the front camera 2 and the front sensor 4. Is less than the steering avoidable distance Ls or the braking avoidable distance Lb, and if the steering intention of the host vehicle 1 by the driver is not detected, the steering actuator 18 restricts the steering of the host vehicle 1 and the brake 28 Since the host vehicle 1 is decelerated by this, braking and steering of the host vehicle 1 can be prevented and the frictional force generated between the tire and the road surface can be effectively used as a braking force. In addition, the driver who does not intend to steer the host vehicle 1 can reliably prevent a collision with a front obstacle by braking the host vehicle 1 without feeling uncomfortable. It can be.

  In addition, the control unit 24 determines that the difference between the braking avoidable distance Lb and the steering avoidable distance Ls is less than the predetermined value β, and the vehicle 1 to the front obstacle detected by the front camera 2 and the front sensor 4. If the driver's intention to steer the host vehicle 1 is detected when the distance Lo is equal to or less than the steering avoidable distance Ls or the brake avoidable distance Lb, braking of the host vehicle 1 is restricted and the steering actuator 18 Since the steering of the vehicle 1 is allowed, the braking and steering of the host vehicle 1 can be prevented and the frictional force generated between the tire and the road surface can be effectively used as a cornering force. Thus, the driver who intends to steer the host vehicle 1 reliably turns the collision with the front obstacle by steering the host vehicle 1 without making the driver feel uncomfortable. It can be.

  In addition, the control unit 24 determines that the difference between the braking avoidable distance Lb and the steering avoidable distance Ls is less than the predetermined value β, and the vehicle 1 to the front obstacle detected by the front camera 2 and the front sensor 4. When the rear side sensor 6 detects a rear side vehicle when the distance Lo is equal to or less than the steering avoidable distance Ls or the braking avoidable distance Lb, whether or not the driver intends to steer the host vehicle 1 Regardless of this, since the steering actuator 18 restricts the steering of the host vehicle 1 and the brake 28 decelerates the host vehicle 1, the frictional force generated between the tire and the road surface is effectively used as a braking force. The host vehicle 1 can be sufficiently decelerated, so that the rear vehicle approaches the side of the host vehicle 1 so that the host vehicle 1 can collide with a front obstacle. The collision with the forward obstacle even when it becomes impossible to steer to avoid can be reliably avoided by the braking of the vehicle 1.

  In addition, the control unit 24 can avoid the braking avoidable distance Lb that is longer than the steering avoidable distance Ls and the distance Lo from the host vehicle 1 to the front obstacle detected by the front camera 2 or the front sensor 4. If the driver's intention to steer the host vehicle 1 is detected when the distance is less than or equal to the distance Lb, the braking of the host vehicle 1 is restricted and the steering of the host vehicle 1 is allowed by the steering actuator 18. In spite of the situation where the collision of the vehicle 1 can be avoided only by the steering of the host vehicle 1, the steering of the host vehicle 1 can be prevented from being restricted against the intention of the driver, and the friction force generated between the tire and the road surface can be reduced. It can be used effectively as a cornering force, and this does not cause a driver who intends to steer the vehicle 1 to feel uncomfortable. The collision with the forward obstacle can be reliably avoided by the steering of the vehicle 1.

  Particularly, the braking avoidable distance Lb is longer than the steering avoidable distance Ls, and the distance Lo from the host vehicle 1 to the front obstacle detected by the front camera 2 or the front sensor 4 is equal to or less than the braking avoidable distance Lb. If the driver's intention to steer the host vehicle 1 is detected when the steering avoidance distance Ls is longer, the brake 28 decelerates the host vehicle 1 at a deceleration equal to or less than the intermediate deceleration Dmid, and the steering actuator 18 Since the steering of the vehicle 1 is allowed, it is possible to prevent the steering of the host vehicle 1 from being restricted against the driver's intention despite the situation in which the collision with the front obstacle can be avoided only by the steering of the host vehicle 1. The host vehicle 1 can be decelerated without affecting the avoidance of a collision with a front obstacle due to the steering of the host vehicle 1, The collision with the forward obstacle without feeling uncomfortable to the intention of a certain driver to perform steering of the vehicle 1 can be reliably avoided by the steering of the vehicle 1.

  In addition, the control unit 24 can avoid the braking avoidable distance Lb that is longer than the steering avoidable distance Ls and the distance Lo from the host vehicle 1 to the front obstacle detected by the front camera 2 or the front sensor 4. When the rear side sensor 6 detects a rear side vehicle when the distance Ls is equal to or less than the distance Ls, the steering actuator 18 determines whether or not the vehicle 1 of the host vehicle 1 is detected regardless of whether or not the driver intends to steer the host vehicle 1. Since the steering is limited, the friction force generated between the tire and the road surface can be effectively used as a braking force, so that the host vehicle 1 can be sufficiently decelerated. By approaching to the side, even if the host vehicle 1 is unable to steer to avoid a collision with a front obstacle, the collision with the front obstacle is reliably ensured by braking the host vehicle 1. It can be avoided.

  Further, since the steering actuator 18 applies assist torque corresponding to the driver's steering operation to the steering mechanism of the host vehicle 1, the driver is intended to steer the host vehicle 1 to the front obstacle without making the driver feel uncomfortable. Can be reliably avoided by steering the host vehicle 1.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Front camera 4 Front sensor 6 Rear side sensor 8 Occupant sensor 10 Pedal stroke sensor 12 Direction indicator switch 14 Steering wheel 16 Steering shaft 18 Steering actuator 20 Vehicle speed sensor 22 Steering angle sensor 24 Control unit 26 Engine 28 Brake

Claims (4)

A control device for a vehicle that controls the host vehicle so as to avoid a collision with a front obstacle existing in front of the host vehicle,
Braking control means for controlling braking of the host vehicle;
Steering control means for controlling the steering of the host vehicle;
Forward obstacle detection means for detecting the distance from the host vehicle to the front obstacle and the relative speed of the host vehicle with respect to the front obstacle;
Steering intention detection means for detecting the steering intention of the host vehicle by the driver;
Based on the relative speed of the host vehicle to the front obstacle detected by the front obstacle detection means, the shortest distance between the front obstacle and the host vehicle that can avoid a collision with the front obstacle only by steering the host vehicle. A steering avoidable distance acquisition means for acquiring a steering avoidable distance;
Based on the relative speed of the host vehicle to the front obstacle detected by the front obstacle detection means, the shortest distance between the front obstacle and the host vehicle that can avoid a collision with the front obstacle only by braking the host vehicle. Braking avoidable distance acquisition means for acquiring a braking avoidable distance; and
The difference between the braking avoidable distance and the steering avoidable distance is less than a predetermined value, and the distance from the host vehicle to the front obstacle detected by the front obstacle detecting means is the steering avoidable distance or the above The collision avoidance control means for limiting the steering of the host vehicle by the steering control means and decelerating the host vehicle by the braking control means when the driver's intention to steer the host vehicle is not detected when the distance is less than the braking avoidable distance. When,
A vehicle control apparatus comprising:   The collision avoidance control means has a difference between the braking avoidable distance and the steering avoidable distance that is less than a predetermined value, and the distance from the host vehicle to the front obstacle detected by the front obstacle detecting means is If the steering intention of the host vehicle is detected by the driver when the steering avoidable distance or the braking avoidable distance is less than or equal to the braking avoidable distance, the braking control unit restricts the braking of the host vehicle and the steering control unit The vehicle control device according to claim 1, wherein steering of the vehicle is allowed. Furthermore, it has a rear side vehicle detection means for detecting a rear side vehicle traveling behind the host vehicle,
The collision avoidance control means has a difference between the braking avoidable distance and the steering avoidable distance that is less than a predetermined value, and the distance from the host vehicle to the front obstacle detected by the front obstacle detecting means is Whether the steering intention of the host vehicle by the driver is detected or not when the rear side vehicle detecting means detects the rear side vehicle when the steering avoidable distance or the braking avoidable distance is equal to or less. The vehicle control device according to claim 2, wherein the steering control unit restricts the steering of the host vehicle and the braking control unit decelerates the host vehicle.   4. The vehicle control device according to claim 1, wherein the steering control unit applies an assist torque corresponding to a driver's steering operation to a steering mechanism of the host vehicle. 5.

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