Method and apparatus for assisting vehicle operator braking action of a vehicle

• US 6,415,230 B1
• Filed: 08/18/2000
• Issued: 07/02/2002
• Est. Priority Date: 09/06/1999
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Inoue, Hideaki, Kobayashi, Akihiko, Tamura, Minoru, Maruko, Naoki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/640,792
• Time in Patent Office: 683 Days
• Field of Search: 701/301, 701/30, 701/70, 701/96, 340/463, 340/435, 340/436, 340/903, 340/901, 340/71, 180/169, 180/170, 180/167, 180/171, 342/70, 342/129, 345/39, 362/555
• US Class Current: 701/301
• CPC Class Codes: B60T 13/72 in vacuum systems or vacuum booster units
• CPC Class Codes: B60T 2201/12 Pre-actuation of braking systems without significant braking effect; Optimizing brake performance by reduction of play between brake pads and brake disc
• 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 8/4854 pneumatic boosters

Abstract

A method and apparatus for assisting operation by a vehicle operator for braking of a vehicle includes a detection system on the vehicle, which detects obstacles located in or near the direction of motion of the vehicle. Vehicle condition sensors on the vehicle provide characteristic parameters of the condition of the vehicle. Operator demand sensors, which are operatively associated with a brake pedal and an accelerator pedal, provide operator demands on the vehicle. A control unit determines whether or not braking action by the vehicle operator is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure. The control unit is operable to generate a command for adjustment of brake pressure to the determined stand-by brake pressure. A braking system on the vehicle is operable by the vehicle operator. The braking system is operable in response to the command to trigger stand-by brake pressure regulation upon determination that braking action by the vehicle operator is needed.

Claims

1. An apparatus for assisting vehicle operator braking action of a vehicle, comprising:

a detection system that detects obstacles located in or near the direction of motion of the vehicle;

vehicle condition sensors that provide characteristic parameters of the condition of the vehicle;

operator demand sensors that provide operator demand;

a control unit that determines whether braking action is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure, said control unit being operable to generate a command for adjustment of brake pressure to said determined stand-by brake pressure; and

a braking system operable by the vehicle operator, said braking system being operable in response to said command to trigger stand-by brake pressure regulation upon said control unit determining that braking action is needed.

2. The apparatus as claimed in claim 1, wherein said control unit increases the target stand-by brake pressure as speed ratio in a transmission, which is available upon said control unit determining that braking action is needed, decreases.

3. The apparatus as claimed in claim 1, wherein said control unit increases the target stand-by brake pressure as traveling speed of the vehicle, which is available upon said control unit determining that braking action is needed, increases.

4. The apparatus as claimed in claim 1, wherein said control unit increases the target stand-by brake pressure greater as the maximum release speed of an accelerator pedal of the vehicle, which is available upon said control unit determining that braking action is needed, increases.

5. The apparatus as claimed in claim 1, wherein said control unit increases the target stand-by brake pressure as weight of the vehicle increases.

6. The apparatus as claimed in claim 1, wherein said control unit continuously calculates a target deceleration as a function of a distance between the vehicle and an obstacle and a relative speed between the vehicle and an obstacle and wherein said control unit determines that braking action is needed immediately after said control unit has determined that the magnitude of said calculated target deceleration has exceeded a predetermined magnitude of deceleration.

7. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure determined by said control unit is a function of travelling speed of the vehicle.

8. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure determined by said control unit is a function of weight of the vehicle.

9. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure is a function of accelerator pedal release speed upon returning movement of an accelerator pedal of the vehicle toward a released position thereof.

10. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure is a function of coefficient of friction between road tires of the vehicle and the surface of a roadway on which the vehicle is travelling.

11. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure is a function of a speed ratio established by a transmission of the vehicle.

12. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure drops in response to time elapsed since said control unit has determined that braking action was needed.

13. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure gradually drops as time elapses since said control unit has determined that braking action was needed.

14. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure remains unaltered for a preset period of time since said control unit has determined that braking action was needed and drops gradually as time elapses thereafter.

15. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure drops to zero upon elapse of a preset period of time since said control unit determined that braking action was needed.

16. The apparatus as claimed in claim 1, where said target standby brake pressure drops to zero when said control unit determines an actual braking action.

17. The apparatus as claimed in claim 1, wherein said target stand-by brake pressure drops to zero when said control unit determines an actual accelerating action.

18. The apparatus as claimed in claim 1, wherein said braking system is operable in response to said command to trigger a stand-by state requiring stand-by brake pressure regulation upon said control unit determining that braking action is needed, and wherein the stand-by state is terminated upon the control unit determining an acceleration action or a braking action by the vehicle operator.

19. An apparatus for assisting vehicle operator braking action of a vehicle, comprising:

a detection system that detects obstacles located in or near the direction of motion of the vehicle;

vehicle condition sensors that provide characteristic parameters of the condition of the vehicle;

operator demand sensors that provide operator demand;

a control unit that determines whether braking action is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure, said control unit being operable to generate a command for adjustment of brake pressure to said determined stand-by brake pressure; and

a braking system operable by the vehicle operator, said braking system being operable in response to said command to trigger stand-by brake pressure regulation upon said control unit determining that braking action is needed,

wherein said determined target stand-by brake pressure has an initial level greater than zero immediately after an accelerator pedal of the vehicle has been released by the vehicle operator, but said determined target stand-by brake pressure drops from said initial level toward zero level in response to elapse of time from the moment when the accelerator pedal has been released by the vehicle operator, and wherein said braking system is operable in response to said command to provide brake pressure as high as said determined target pressure.

20. The apparatus as claimed in claim 19, wherein said determined target pressure drops to zero level upon elapse of a preset period of time from the moment when the accelerator pedal has been released by the vehicle operator.

21. The apparatus as claimed in claim 19, wherein said determined target pressure drops from said initial level gradually toward zero in response to elapse of time from the moment when the accelerator pedal has been released by the vehicle operator, and finally drops to zero level.

22. The apparatus as claimed in claim 19, wherein said determined target pressure remains unaltered at said initial level for a preset period of time from the moment when the accelerator pedal has been released by the vehicle operator and drops from said initial level gradually toward zero in response to elapse of time after expiration of said preset period of time, and finally drops to zero level.

23. The apparatus as claimed in claim 19, wherein said determined target pressure drops from said initial level down to zero level upon subsequent depression of the accelerator pedal by the vehicle operator.

24. The apparatus as claimed in claim 19, wherein said determined target pressure drops from said initial level down to zero level upon subsequent depression of a brake pedal of said braking system by the vehicle operator.

25. A method for assisting vehicle operator braking action of a vehicle, comprising:

detecting obstacles located in or near the direction of motion of the vehicle;

providing characteristic parameters of the condition of the vehicle;

providing operator demand;

determining whether braking action is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure;

generating a command for adjustment of brake pressure to said determined stand-by brake pressure; and

triggering stand-by brake pressure regulation in response to said command upon said control unit determining that braking action is needed.

26. The method of claim 25, wherein in the triggering a stand-by brake pressure regulation step, a stand-by state is triggered requiring stand-by brake pressure regulation in response to said command upon said control unit determining that braking action is needed;

and further comprising;

terminating the stand-by state upon determining an acceleration action or a braking action by the vehicle operator.

27. A apparatus for assisting vehicle operator braking action of a vehicle, comprising:

means for detecting obstacles located in or near the direction of motion of the vehicle;

means for providing characteristic parameters of the condition of the vehicle;

means for providing operator demand;

means for determining whether braking action is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure;

means for generating a command for adjustment of brake pressure to said determined stand-by brake pressure; and

means for triggering requiring stand-by brake pressure regulation in response to said command upon said control unit determining that braking action is needed.

28. The apparatus of claim 27, wherein the means for triggering stand-by brake pressure regulation comprises means for triggering a stand-by state requiring stand-by brake pressure regulation in response to said command upon said control unit determining that braking action is needed, wherein the stand-by state is terminated upon determining an acceleration action or a braking action by the vehicle operator.

29. An apparatus for assisting vehicle operator braking action of a vehicle, comprising:

a detection system that detects obstacles located in or near the direction of motion of the vehicle;

vehicle condition sensors that provide characteristic parameters of the condition of the vehicle;

operator demand sensors that provide operator demand;

a control unit that determines whether braking action is needed from data concerning the obstacles, the characteristic parameters of vehicle condition and the operator demands on the vehicle and determines a target stand-by brake pressure, said control unit being operable to generate a command for adjustment of brake pressure to said determined stand-by brake pressure upon said control unit determining that braking action is needed and upon said operator demand sensors providing that there is no operator demand for braking action; and

a braking system operable by the vehicle operator, said braking system adjusting the brake pressure to said determined stand-by brake pressure upon the control unit generating said command to trigger stand-by brake pressure, said braking system being operable in response to said command to trigger stand-by brake pressure regulation upon said control unit determining that braking action is needed.