Method and device for improving the handling characteristics of a vehicle while braking during cornering

• US 6,273,529 B1
• Filed: 08/10/2000
• Issued: 08/14/2001
• Est. Priority Date: 12/20/1997
• Status: Expired due to Term

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Waldbauer, Dirk, Woywod, Jürgen, Roll, Georg
• Primary Examiner(s): Swann, J. J.
• Assistant Examiner(s): DIVINE, DAVID A
• Application Number:
  US09/581,979
• Time in Patent Office: 369 Days
• Field of Search: 303/139, 303/122.01, 303/167, 303/169, 303/173, 303/155, 303/147, 303/176, 303/148, 303/146, 188/3.H
• US Class Current: 303/173
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 2220/03 Driver counter-steering; Avoidance of conflicts with ESP control
• 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

Abstract

A system including a method for improving the driving performance of a vehicle when braking during cornering comprises the following steps: detecting cornering and the direction of cornering, determining the rolling characteristics of individual wheels, if necessary, influencing the braking pressure of the brake on one wheel or on several wheels according to the rolling characteristics of these wheels, checking the driving condition of the vehicle with respect to whether instability prevails, and modifying the braking pressure of at least one brake of a wheel when an instability is detected during a cornering maneuver extending for a time period that reaches a threshold time period. A device for improving the driving performance of a vehicle while braking during cornering comprises a detection device for detecting a cornering maneuver and the direction of cornering, a determining device for determining the rolling characteristics of individual wheels, an influencing device which optionally influences the braking pressure of the brake on one wheel, a checking device for checking the driving condition of the vehicle as to whether instability prevails, and a modifying device for modifying the braking pressure of at least one brake of a wheel when an instability is detected during cornering extending for a time period which reaches a threshold time period.

Claims

1. Method of improving the driving performance of a vehicle when braking during cornering, comprising the following steps:

detecting cornering and the direction of cornering,

determining the rolling characteristics of individual wheels, and if necessary, influencing the braking pressure of the brake on one wheel or on several wheels according to the rolling characteristics of these wheels,

checking the driving condition of the vehicle with respect to whether instability prevails,

modifying the braking pressure of at least one brake of a wheel when an instability is detected during cornering which persists beyond a predetermined time period, and

identifying a critical lane change if, within a defined or definable duration after cornering in the unstable condition in one direction, there is detected cornering in the unstable condition to the other direction, and further measures are initiated upon the detection.

2. Method as claimed in claim 1, wherein the modifying is effected in such a manner that the braking pressure on at least one wheel on the inside of a bend is decreased or the braking pressure on at least one wheel on the outside of the bend is increased.

3. Method as claimed in claim 1, wherein the modifying is effected in such a manner that the braking pressures on the wheels of the rear axle are decreased.

4. Method as claimed in claim 1, wherein the modifying includes changing the braking pressure of at least one brake during cornering in the time period before the threshold time period is reached.

5. Method as claimed in claim 4, wherein the changing step further includes increasing the braking pressure on at least one wheel on the inside of a bend or decreasing the braking pressure on at least one wheel on the outside of the bend.

6. Method as claimed in claim 1, wherein the modifying step is omitted or discontinued when a countersteering maneuver or cornering in opposite direction is detected or after unstable cornering is terminated.

7. Method as claimed in claim 6, further including the step of determining the time period of instability during cornering by way of the control cycles of an ABS system.

8. Method as claimed in claim 1, further including the step of comparing signals generated from the wheels of one axle and using those signals to determine driving conditions.

9. Method as claimed in claim 8, further including inferring instability when one wheel of the axle, contrary to the other one, exhibits a considerable amount of slip, or when the braking pressure is influenced on one wheel of the axle, to a weaker extent on the other one, or is not influenced at all.

10. Method as claimed in claim 1, wherein cornering is detected by referencing the rolling characteristics of wheels of one axle.

11. Method as claimed in claim 1, wherein cornering is detected by making reference to a steering angle sensor.

12. Method as claimed in claim 1, wherein the duration is determined according to the coefficient of function between the wheel and the road surface, further including adjusting the duration upwardly as the coefficient of friction decreases.

13. Method as claimed in claim 1, wherein modifying the braking pressure includes changing the threshold values which are taken into account for influencing the braking pressure.

14. Device for improving the driving performance of a vehicle during braked cornering, including

a detection device for detecting cornering and the direction of cornering,

a determining device for determining the rolling characteristics of individual wheels,

an influencing device which influences, if necessary, the braking pressure of the brake on a wheel according to the rolling characteristics of this wheel,

a checking device for checking the driving condition of the vehicle as to whether instability prevails, and

a modifying device for modifying the braking pressure of at least one brake of a wheel when an instability is detected during cornering over a time period that reaches a threshold time period, wherein the influencing device is an ABS system, and there is provision of a time determining device which determines the time period of the instability during cornering by way of the control cycles of the ABS system, and wherein the time determining device includes a counter with a predetermined counter value which is incremented or decremented according to the direction of the bend when unstable cornering is detected, there being provision of a top and a bottom threshold value which produce the threshold time period.

15. Device as claimed in claim 14, wherein the modifying device decreases the braking pressure on at least one wheel on the inside of a bend or increases it on at least one wheel on the outside of the bend.

16. Device as claimed in claim 14, wherein the modifying device decreases the braking pressures on the wheels of the rear axle.

17. Device as claimed in claim 14, further including a changing device which changes the braking pressure of at least one brake during cornering in the time period before the threshold time period is reached.

18. Device as claimed in claim 17, wherein the changing device increases the braking pressure on at least one wheel on the inside of a bend or decreases it on at least one wheel on the outside of the bend.

19. Device as claimed in claim 14, wherein the modifying device omits or discontinues the modification when a countersteering maneuver or cornering in the other direction is detected.

20. Device as claimed in claim 14, wherein the fixed counter reading is zero, the one threshold value is lower than zero, and the other threshold value exceeds zero.

21. Device as claimed in claim 14, wherein the counter is counted upwards or downwards until a top or a bottom limit value, the top limit value being above the top threshold value and the bottom limit value below the bottom threshold value.

22. Device as claimed in claim 14, wherein the counter is restored stepwise to the fixed counter reading when no cornering maneuver is detected.

23. Device as claimed in claim 14, wherein when a cornering maneuver in one direction is detected which is opposite to the direction that corresponds to the counter reading, the counter is quickly restored to the fixed counter reading.

24. Device as claimed in claim 14, further including:

a gate time device which defines a gate time after the end of a critical cornering maneuver,

a gathering device which concludes a critical lane change when a critical cornering maneuver in the other direction is detected during the gate time, and

an alteration device which alters the braking pressure on one or more of the wheels when a critical lane change is detected.

25. Device as claimed in claim 24, wherein the gate time device includes a counter which is counted downwards from an initial counter reading, and the initial counter reading is set according to the coefficient of friction between the wheel and the road surface.

26. Device as claimed in claim 14, wherein the checking device includes a comparison device which compares data or values of the wheels of an axle.

27. Device as claimed in claim 14, wherein the detection device includes a comparison device which compares data or values of the wheels of an axle.

28. Device as claimed in claim 14, wherein at least one of the modifying device, the changing device, and the alteration device includes a device for changing the threshold values which are taken into account for influencing the braking pressure.