Soft-stop braking control

• US 20070182243A1
• Filed: 02/03/2006
• Published: 08/09/2007
• Est. Priority Date: 02/03/2006
• Status: Active Grant

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Techentin, James, Osborn, Douglas
• Granted Patent: US 7,475,953 B2
• Time in Patent Office: Days
• US Class Current: 303/10
• CPC Class Codes: B60T 2201/02 Active or adaptive cruise control system; Distance control
• CPC Class Codes: B60T 2230/04 Jerk, soft-stop; Anti-jerk, reduction of pitch or nose-dive when braking
• 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 8/00 Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force by changing number of effective brake cylinders in power brake systems B60T17/10

Abstract

A method is provided for applying a soft-stop control to the vehicle brake actuators of a vehicle during a vehicle stop operation. A brake apply operation is detected. A determination is made whether the vehicle speed is below a first threshold stopping speed. Braking pressure to the vehicle actuators is reduced as a function of vehicle speed, vehicle deceleration, and brake apply pressure if the vehicle speed is below the first threshold stopping speed.

Claims

1. A method for applying a soft-stop control to the vehicle brake actuators of a vehicle during a vehicle stop operation, said method comprising the steps of:

detecting a brake apply operation;

determining if the vehicle speed is below a first threshold stopping speed; and

reducing braking pressure to said vehicle brake actuators as a function of vehicle speed, vehicle deceleration, and brake apply pressure if said vehicle speed is below said first threshold stopping speed.

2. The method of claim 1 further comprising the step on determining if a secondary braking function is active, wherein said step of reducing said braking pressure is discontinued if a secondary braking function is active during said brake apply operation.

3. The method of claim 2 wherein said secondary braking function includes an anti-lock braking function.

4. The method of claim 2 wherein said secondary braking function includes a corner brake control function.

5. The method of claim 2 wherein said secondary braking function includes a deceleration based isolation function.

6. The method of claim 1 further comprising the step of sensing for a target proximate to said vehicle, wherein said step of reducing said braking pressure is discontinued if a target is sensed within a target distance threshold of said vehicle.

7. The method of claim 6 wherein said target is sensed forward of said vehicle.

8. The method of claim 6 wherein said target is sensed rearward of said vehicle.

9. The method of claim 1 wherein said step of reducing said braking pressure is discontinued if said vehicle speed is less than a second threshold stopping speed.

10. The method of claim 1 wherein said step detecting a brake apply operation comprises sensing said master cylinder pressure greater than a predetermined stop pressure threshold.

11. The method of claim 1 wherein said step detecting a brake apply operation comprises sensing an activation of a brake switch.

12. The method of claim 1 wherein said step detecting a brake apply operation comprises sensing a travel of a brake pedal greater than a predetermined brake pedal distance threshold.

13. The method of claim 1 wherein said step of reducing said braking pressure is discontinued if a rate of change of said brake apply pressure is outside of a predetermined braking rate threshold.

14. The method of claim 13 wherein said rate of change of said brake apply pressure is determined by sensing a rate of change of said master cylinder pressure.

15. The method of claim 13 wherein said rate of change of said brake apply pressure is determined by sensing a change in a travel distance of a brake pedal.

16. A method for applying a soft-stop control to the vehicle brake actuators of a vehicle during a vehicle stop operation, said method comprising the steps of:

detecting a brake apply operation by a driver in response to a master cylinder pressure being above a predetermined braking rate threshold;

determining that a secondary brake operation is inactive;

determining that a vehicle speed is between a first threshold stopping speed and a second threshold stopping speed; and

reducing brake pressure to said vehicle brake actuators as a function of said master cylinder pressure, said vehicle speed, and a vehicle deceleration if said secondary brake operation is inactive and said vehicle speed is between said first and second threshold stopping speed.

17. The method of claim 16 further comprising the step of sensing for a target proximate to said vehicle, wherein said step of reducing said braking pressure to said vehicle brakes is discontinued if a target is sensed rearward of said vehicle is within a target distance threshold.

18. The method of claim 16 wherein said step of reducing said braking pressure is discontinued if a rate of change of said brake pressure is outside of a predetermined braking rate threshold.

19. A method for applying a soft-stop control to the vehicle brake actuators of a vehicle during a vehicle stop operation, said method comprising the steps of:

detecting a brake apply operation by an activation of a brake switch;

determining that a secondary brake operation is inactive;

determining that a vehicle speed is between a first threshold stopping speed and a second threshold stopping speed; and

reducing brake pressure to said vehicle brake actuators as a function of said master cylinder pressure, said vehicle speed, and a vehicle deceleration if said secondary brake operation is inactive and said vehicle speed is between said first and second threshold stopping speed.

20. A method for applying a soft-stop control to the vehicle brake actuators of a vehicle during a vehicle stop operation, said method comprising the steps of:

detecting a brake apply operation by sensing a travel of a brake pedal greater than a predetermined brake pedal travel threshold;

determining that a secondary brake operation is inactive;

determining that a vehicle speed is between a first threshold stopping speed and a second threshold stopping speed; and

reducing brake pressure to said vehicle brake actuators as a function of said master cylinder pressure, said vehicle speed, and a vehicle deceleration if said secondary brake operation is inactive and said vehicle speed is between said first and second threshold stopping speed.