Method and system for turning detection

• US 5,691,900 A
• Filed: 06/30/1995
• Issued: 11/25/1997
• Est. Priority Date: 07/28/1994
• Status: Expired due to Fees

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Luckevich, Mark
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): WALDER, STEPHEN JOSEPH
• Application Number:
  US08/497,409
• Time in Patent Office: 879 Days
• Field of Search: 364/424.05, 364/426.02, 364/426.01, 364/424.051, 364/424.016, 180/197, 303/96, 303/94
• US Class Current: 701/41
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/1764 Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
• CPC Class Codes: B60T 8/1769 specially adapted for vehicles having more than one driven axle, e.g. four-wheel drive vehicles

Abstract

A method and system, for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock brake system (ABS), for detecting when the vehicle is executing a turning maneuver. The system includes means for performing the method steps of determining a speed difference between one pair of the vehicle wheels, determining the deceleration of each of the one pair of vehicle wheels, comparing the speed difference to a turning detection threshold, comparing the decelerations to a deceleration threshold, and detecting a turning maneuver based on those comparisons.

Claims

1. A method for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock brake system (ABS), the method for detecting when the vehicle is executing a turning maneuver, the method comprising:

determining a speed difference between one pair of the vehicle wheels;

determining the deceleration of each wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference;

comparing the speed difference to a turning detection threshold;

comparing the decelerations to a deceleration threshold; and

detecting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold.

2. The method of claim 1 wherein detecting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes setting a turn flag false if the deceleration of either wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference exceeds the deceleration threshold.

3. The method of claim 1 wherein the speed difference is determined based on the speeds of the rear wheels when both pairs of the vehicle wheels are being driven, otherwise the speed difference being determined based on the speeds of the undriven pair of vehicle wheels.

4. The method of claim 1 wherein the speed difference is determined based on the speeds of the front wheels when both pairs of the vehicle wheels are being driven and the vehicle includes a single speed sensor associated with the pair of rear wheels.

5. The method of claim 1 further comprising:

modifying a counter after comparing the wheel decelerations to the deceleration threshold; and

comparing the value of the counter to a hysteresis threshold;

wherein detecting a turning maneuver is based on the comparison of the counter to the hysteresis threshold.

6. The method of claim 1 wherein the comparisons to each of the thresholds are made only if the ABS is not activated.

7. The method of claim 1 wherein the vehicle is travelling on a road surface having at least a low μ

portion and a high μ

portion split along the longitudinal axis of the vehicle, the method further comprising increasing a pressure apply rate for a brake of each wheel travelling on the high μ

portion of the road surface when a turning maneuver has been detected.

8. The method of claim 7 wherein isolation of the brake of each wheel travelling on the high mu portion of the road surface is delayed when a turning maneuver has been detected.

9. The method of claim 1 wherein the vehicle is travelling on a homogeneous road surface and a turning maneuver has been detected such that two of the vehicle wheels become more weighted and two of the vehicle wheels becomes more unweighted, the method further comprising increasing a pressure apply rate for a brake of each of the more weighted vehicle wheels.

10. The method of claim 1 wherein detecting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes setting a turn flag false if the speed difference fails to exceed the turning detection threshold.

11. The method of claim 1 wherein detecting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes setting a turn flag true if the speed difference exceeds the turning detection threshold and the decelerations of both wheels of the one pair of vehicle wheels whose speed was utilized to determine the speed difference fail to exceed the deceleration threshold.

12. A system for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock brake system (ABS), the system for detecting when the vehicle is executing a turning maneuver, the system comprising:

means for determining a speed difference between one pair of the vehicle wheels;

means for determining the deceleration of each wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference;

means for comparing the speed difference to a turning detection threshold;

means for comparing the decelerations to a deceleration threshold; and

means for detecting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold.

13. The system of claim 12 wherein the speed difference is determined based on the speeds of the front wheels when both pairs of the vehicle wheels are being driven and the vehicle includes a single speed sensor associated with the pair of rear wheels.

14. The system of claim 12 further comprising:

a counter, the counter being modified after comparing the wheel decelerations to the deceleration threshold; and

means for comparing the value of the counter to a hysteresis threshold;

wherein the means for detecting a turning maneuver does so based on the comparison of the counter to the hysteresis threshold.

15. The system of claim 12 wherein the comparisons to each of the thresholds are made only if the ABS is not activated.

16. The system of claim 12 wherein the vehicle is travelling on a road surface having at least a low μ

portion and a high μ

portion split along the longitudinal axis of the vehicle, the system further comprising means for increasing a pressure apply rate for a brake of each wheel travelling on the high μ

portion of the road surface when a turning maneuver has been detected.

17. The system of claim 16 wherein isolation of the brake of each wheel travelling on the high mu portion of the road surface is delayed when a turning maneuver has been detected.

18. The system of claim 12 wherein the vehicle is travelling on a homogeneous road surface and a turning maneuver has been detected such that two of the vehicle wheels become more weighted and two of the vehicle wheels becomes more unweighted, the system further comprising means for increasing a pressure apply rate for a brake of each of the more weighted vehicle wheels.

19. The system of claim 12 wherein the speed difference is determined based on the speeds of the rear wheels when both pairs of the vehicle wheels are being driven, otherwise the speed difference being determined based on the speeds of the undriven pair of vehicle wheels.

20. The system of claim 12 wherein the means for detecting includes means for setting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes means for setting a turn flag false if the deceleration of either wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference exceeds the deceleration threshold.

21. The system of claim 12 wherein the means for detecting includes means for setting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes means for setting a turn flag false if the speed difference fails to exceed the turning detection threshold.

22. The system of claim 12 wherein the means for detecting includes means for setting a turning maneuver based on the comparison of the speed difference to the turning detection threshold and the decelerations to the deceleration threshold includes means for setting a turn flag true if the speed difference exceeds the turning detection threshold and the decelerations of both wheels of the one pair of vehicle wheels whose speed was utilized to determine the speed difference fail to exceed the deceleration threshold.

23. A method for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock braking system (ABS), the method for detecting when the vehicle is executing a turning maneuver, the method comprising:

determining a speed difference between one pair of the vehicle wheels;

determining a lateral acceleration of the vehicle based on the speed difference between one pair of the vehicle wheels;

comparing the lateral acceleration to a turning detection threshold;

determining the deceleration of each wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference;

comparing the decelerations to a deceleration threshold; and

detecting a turning maneuver based on the comparison of the lateral acceleration to the turning detection threshold and the decelerations to the deceleration threshold.

24. The method of claim 23 further comprising detecting slip in the pair of rear wheels based on an average speed of the pair of rear wheels when a turning maneuver has been detected.

25. The method of claim 23 wherein the speed difference is determined based on the speeds of an undriven pair of vehicle wheels.

26. The method of claim 23 wherein detecting a turning maneuver based on the comparison of the lateral acceleration to the turning detection threshold and the decelerations to the deceleration threshold includes setting a turn flag true if the lateral acceleration exceeds the turning detection threshold and the decelerations of both wheels of the one pair of vehicle wheels whose speed was utilized to determine the speed difference fail to exceed the deceleration threshold.

27. The method of claim 26 wherein the turn flag is set true only if the ABS is not activated for the one pair of vehicle wheels whose speed was utilized to determine the speed difference.

28. The method of claim 26 wherein the turn flag is set false if the lateral acceleration fails to exceed the turning detection threshold and the ABS is not activated for the one pair of vehicle wheels whose speed was not utilized to determine the speed difference.

29. A system for use with a vehicle including a pair of front wheels, a pair of rear wheels, and an anti-lock braking system (ABS), the system for detecting when the vehicle is executing a turning maneuver, the system comprising:

means for determining a speed difference between one pair of the vehicle wheels;

means for determining a lateral acceleration of the vehicle based on the speed difference between one pair of the vehicle wheels;

means for comparing the lateral acceleration to a turning detection threshold;

means for determining the deceleration of each wheel of the one pair of vehicle wheels whose speed was utilized to determine the speed difference;

means for comparing the decelerations to a deceleration threshold; and

means for detecting a turning maneuver based on the comparison of the lateral acceleration to the turning detection threshold and the decelerations to the deceleration threshold.

30. The system of claim 29 further comprising means for detecting slip in the pair of rear wheels based on an average speed of the pair of rear wheels when a turning maneuver has been detected.

31. The system of claim 29 wherein the speed difference is determined based on the speeds of an undriven pair of vehicle wheels.

32. The system of claim 29 wherein the means for detecting a turning maneuver based on the comparison of the lateral acceleration to the turning detection threshold and the decelerations to the deceleration threshold includes means for setting a turn flag true if the lateral acceleration exceeds the turning detection threshold and the decelerations of both wheels of the one pair of vehicle wheels whose speed was utilized to determine the speed difference fail to exceed the deceleration threshold.

33. The system of claim 32 wherein the turn flag is set true only if the ABS is not activated for the one pair of vehicle wheels whose speed was utilized to determine the speed difference.

34. The system of claim 32 wherein the turn flag is set false if the lateral acceleration fails to exceed the turn detection threshold and the ABS is not activated for the one pair of vehicle wheels whose speed was not utilized to determine the speed difference.