Forward Collision Avoidance Assistance System

• US 20090143951A1
• Filed: 11/13/2008
• Published: 06/04/2009
• Est. Priority Date: 11/16/2007
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yokoyama, Atsushi, Takahashi, Junya, Kuragaki, Satoru
• Application Number:
  US12/270,332
• Publication Number:
  US 20090143951A1
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 2201/022 Collision avoidance systems
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60T 8/17558 specially adapted for collision avoidance or collision mitigation road vehicle drive control systems for collision avoidance otherwise than by controlling a particular sub-unit B60W30/09
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2510/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2554/801 Lateral distance
• CPC Class Codes: B60W 2554/804 Relative longitudinal speed
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2710/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 2710/207 Steering angle of wheels
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B60W 30/18136 : Engine braking
• CPC Class Codes: B60W 50/14 : Means for informing the driver, warning the driver or prompting a driver intervention

Abstract

An object of the present invention is to provide a forward collision avoidance assistance system that attains the reduction of driver'"'"'s uncomfortable feeling and the improvement in drivability while ensuring the collision avoidance performance during operation for avoiding contact with an object.

A collision avoidance calculation unit 3 determines a risk of collision between a host vehicle and an object detected in the host vehicle traveling direction based on information about the host vehicle detected by a host vehicle information detection unit 1 and information about the object detected by an object information detection unit 2, and calculates control information for object avoidance to be output to an actuator 5 based on a result of collision risk judgment. The collision avoidance calculation unit 3 uses a collision-avoidable limit distance Δxctl2 determined based on a physical limit that can avoid collision with the object, and a jerk-limited collision avoidable distance Δxctl1 determined based on the acceleration and jerk generated on the host vehicle by object avoidance movement, to control the brake force generated on the host vehicle by a brake actuator 5.

Claims

1. A forward collision avoidance assistance system comprising collision avoidance calculation means for calculating control information for judging the risk of collision between the host vehicle and the object detected in the host vehicle traveling direction based on the information on a host vehicle detected by the host vehicle information detection means and the information on the object detected by object information detection means, and calculating the control information for collision avoidance to be output to an actuator based on the result of the collision risk judgment;

wherein the actuator is brake force control means capable of controlling the brake force of the host vehicle; and

wherein the collision avoidance calculation means causes the brake force control means to control the brake force of the host vehicle with the use of a collision-avoidable limit distance Δ

xctl2 determined based on a physical limit above which collision between the host vehicle and the object cannot be avoided and a jerk-limited collision avoidable distance Δ

xctl1 determined based on the acceleration and jerk generated on the host vehicle by the host vehicle'"'"'s object avoidance movement.

2. The forward collision avoidance assistance system according to claim 1,

wherein the collision avoidance calculation means defines the collision-avoidable limit distance Δ

xctl2 based on a deceleration-based collision-avoidable limit distance Δ

xbrk, that is, a physical limit for avoiding collision with the object by the deceleration of the host vehicle, and a lateral-motion-based collision-avoidable limit distance Δ

xstr, that is, a physical limit for avoiding collision with the object by the lateral movement of the host vehicle, and

defines the jerk-limited collision avoidable distance Δ

xctl1 based on a jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt in which the absolute value of the jerk generated on the host vehicle by the deceleration-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit longitudinal jerk |Jxlmt|) and based on a jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt in which the absolute value of the jerk generated on the host vehicle by lateral-motion-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit lateral jerk |Jylmt|).

3. The forward collision avoidance assistance system according to claim 1,

wherein the collision avoidance calculation means calculates the collision-avoidable limit distance Δ

xctl2 and the jerk-limited collision avoidable distance Δ

xctl1 based on road surface information.

4. The forward collision avoidance assistance system according to claim 3,

wherein the collision avoidance calculation means presumes the road surface information based on a brake force generated for each tire by the brake force control means.

5. The forward collision avoidance assistance system according to claim 1,

wherein the collision avoidance calculation means controls the opening angle of a throttle valve to limit the absolute values of the jerks to a predetermined value or below.

6. The forward collision avoidance assistance system according to claim 1,

wherein the actuator serves as lateral force control means for controlling the lateral force of the host vehicle as well as serving as the brake force control means

and wherein the collision avoidance calculation means causes the brake force control means to control the brake force and lateral force of the host vehicle with the use of the collision-avoidable limit distance Δ

xctl2 determined based on a physical limit above which collision between the host vehicle and the object cannot be avoided and the jerk-limited collision avoidable distance Δ

xctl1 determined based on the acceleration and jerk generated on the host vehicle by the host vehicle'"'"'s object avoidance movement.

7. The forward collision avoidance assistance system according to claim 6,

wherein the collision avoidance calculation means defines the collision-avoidable limit distance Δ

xctl2 based on the deceleration-based collision-avoidable limit distance Δ

xbrk, that is, a physical limit for avoiding collision with the object by the deceleration of the host vehicle, and the lateral-motion-based collision-avoidable limit distance Δ

xstr, that is, a physical limit for avoiding collision with the object by the lateral movement of the host vehicle, and

defines the jerk-limited collision avoidable distance Δ

xctl1 based on the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt in which the absolute value of the jerk generated on the host vehicle by the deceleration-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit longitudinal jerk |Jxlmt|) and based on the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt in which the absolute value of the jerk generated on the host vehicle by lateral-motion-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit lateral jerk |Jylmt|).

8. The forward collision avoidance assistance system according to claim 7,

wherein the collision avoidance calculation means controls the deceleration of the host vehicle using the brake force control means and then controls the lateral force using the lateral force control means.

9. The forward collision avoidance assistance system according to claim 7, wherein

if:

a region A1 is defined as a region where a collision-avoidable limit distance in relation to a relative velocity Δ

V is larger than both the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A2 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and larger than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A3 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt and larger than the lateral-motion-based collision-avoidable limit distance Δ

xstr and the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt;

a region A4 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the deceleration-based collision-avoidable limit distance Δ

xbrk and larger than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A5 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the lateral-motion-based collision-avoidable limit distance Δ

xstr and larger than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt;

a region A6 is defined as a region where the collision-avoidable limit distance is equal to or smaller than both the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt and equal to or larger than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the lateral-motion-based collision-avoidable limit distance Δ

xstr;

a region A7 is defined as a region where the collision-avoidable limit distance is smaller than the deceleration-based collision-avoidable limit distance Δ

xbrk, equal to or smaller than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt, and equal to or larger than the lateral-motion-based collision-avoidable limit distance Δ

xstr;

a region A8 is defined as a region where the collision-avoidable limit distance is smaller than the lateral-motion-based collision-avoidable limit distance Δ

xstr, equal to or smaller than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt, and equal to or larger than the deceleration-based collision-avoidable limit distance Δ

xbrk; and

a region A9 is defined as a region where the collision-avoidable limit distance is smaller than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the lateral-motion-based collision-avoidable limit distance Δ

xstr,

the collision avoidance calculation means does not perform collision avoidance control when the collision-avoidable limit distance in relation to the relative velocity Δ

V is included in the region A1, A2, A3, A4, or A5;

decelerates the vehicle at a maximum possible acceleration |Gmax| in the region A9;

in the region A6, sets a deceleration rate such that the longitudinal jerk generated by deceleration-based collision avoidance movement becomes equal to or smaller than a maximum possible longitudinal jerk |Jxmax| or sets a lateral acceleration rate such that the lateral jerk generated by lateral-motion-based collision avoidance movement becomes equal to or smaller than a maximum possible lateral jerk |Jymax|;

sets the lateral acceleration rate to the maximum lateral jerk |Jymax| or below in the region A7; and

sets the deceleration rate to the maximum longitudinal jerk |Jxmax| or below in the region A8.

10. A forward collision avoidance assistance system comprising collision avoidance calculation means for judging the risk of collision between the host vehicle and the object detected in the host vehicle traveling direction based on the information on the host vehicle detected by the host vehicle information detection means and the information on the object detected by object information detection means, and calculating the control information for collision avoidance to be output to an actuator based on the result of the collision risk judgment;

wherein the actuator is brake force control means capable of controlling the brake force of the host vehicle and also lateral force control means capable of controlling the lateral force of the host vehicle; and

wherein the collision avoidance calculation means causes the brake force control means to control the brake force and lateral force of the host vehicle with the use of a collision-avoidable limit distance Δ

xctl2 determined based on a physical limit above which collision between the host vehicle and the object cannot be avoided and a jerk-limited collision avoidable distance Δ

xctl1 determined based on the acceleration and jerk generated on the host vehicle by the host vehicle'"'"'s object avoidance movement.

11. The forward collision avoidance assistance system according to claim 10,

wherein the collision avoidance calculation means defines the collision-avoidable limit distance Δ

xctl2 based on a deceleration-based collision-avoidable limit distance Δ

xbrk, that is, a physical limit for avoiding collision with the object by the deceleration of the host vehicle, and a lateral-motion-based collision-avoidable limit distance Δ

xstr, that is, a physical limit for avoiding collision with the object by the lateral movement of the host vehicle, and

defines the jerk-limited collision avoidable distance Δ

xctl1 based on a jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt in which the absolute value of the jerk generated on the host vehicle by the deceleration-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit longitudinal jerk |Jxlmt|) and based on a jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt in which the absolute value of the jerk generated on the host vehicle by lateral-motion-based collision avoidance movement of the host vehicle is equal to or smaller than a predetermined value (upper-limit lateral jerk |Jylmt|).

12. The forward collision avoidance assistance system according to claim 11,

wherein the collision avoidance calculation means controls the deceleration of the host vehicle using the brake force control means and then controls the lateral force using the lateral force control means.

13. The forward collision avoidance assistance system according to claim 11, wherein

if:

a region A1 is defined as a region where a collision-avoidable limit distance in relation to a relative velocity Δ

V is larger than both the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A2 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and larger than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A3 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt and larger than the lateral-motion-based collision-avoidable limit distance Δ

xstr and the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt;

a region A4 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the deceleration-based collision-avoidable limit distance Δ

xbrk and larger than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt;

a region A5 is defined as a region where the collision-avoidable limit distance is equal to or smaller than the lateral-motion-based collision-avoidable limit distance Δ

xstr and larger than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt;

a region A6 is defined as a region where the collision-avoidable limit distance is equal to or smaller than both the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt and the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt and equal to or larger than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the lateral-motion-based collision-avoidable limit distance Δ

xstr;

a region A7 is defined as a region where the collision-avoidable limit distance is smaller than the deceleration-based collision-avoidable limit distance Δ

xbrk, equal to or smaller than the jerk-limited lateral-motion-based collision avoidable distance Δ

xstrlmt, and equal to or larger than the lateral-motion-based collision-avoidable limit distance Δ

xstr;

a region A8 is defined as a region where the collision-avoidable limit distance is smaller than the lateral-motion-based collision-avoidable limit distance Δ

xstr, equal to or smaller than the jerk-limited deceleration-based collision avoidable distance Δ

xbrklmt, and equal to or larger than the deceleration-based collision-avoidable limit distance Δ

xbrk; and

a region A9 is defined as a region where the collision-avoidable limit distance is smaller than both the deceleration-based collision-avoidable limit distance Δ

xbrk and the lateral-motion-based collision-avoidable limit distance Δ

xstr,

the collision avoidance calculation means does not perform collision avoidance control when the collision-avoidable limit distance in relation to the relative velocity Δ

V is included in the region A1, A2, A3, A4, or A5;

decelerates the vehicle at a maximum possible acceleration |Gmax| in the region A9;

in the region A6, sets a deceleration rate such that the longitudinal jerk generated by deceleration-based collision avoidance movement becomes equal to or smaller than a maximum possible longitudinal jerk |Jxmax| or sets a lateral acceleration rate such that the lateral jerk generated by lateral-motion-based collision avoidance movement becomes equal to or smaller than a maximum possible lateral jerk |Jymax|;

sets the lateral acceleration rate to the maximum lateral jerk |Jymax| or below in the region A7; and

sets the deceleration rate to the maximum longitudinal jerk |Jxmax| or below in the region A8.