METHOD AND APPARATUS OF CONTROLLING AN AUTOMOTIVE VEHICLE USING BRAKE-STEER AS A FUNCTION OF STEERING WHEEL TORQUE

• US 20050236896A1
• Filed: 03/18/2004
• Published: 10/27/2005
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Offerle, Timothy G., Stephan, Craig H., Tseng, Hongtei E.
• Granted Patent: US 7,165,644 B2
• Time in Patent Office: Days
• US Class Current: 303/146
• CPC Class Codes: B60T 2201/10 Automatic or semi-automatic parking aid systems
• CPC Class Codes: B60T 2230/06 Tractor-trailer swaying
• 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: B60W 30/045 Improving turning performance
• CPC Class Codes: B62D 11/001 control systems B62D11/183 takes precedence
• CPC Class Codes: B62D 9/002 combined with means for differentially distributing power on the deflectable wheels during cornering

Abstract

A method of controlling an automotive vehicle having a turning radius includes determining a hand wheel torque and applying brake-steer as a function of hand wheel torque.

Claims

1. A method of controlling an automotive vehicle having a turning radius comprising:

determining a hand wheel torque; and

applying brake-steer as a function of hand wheel torque.

2. A method as recited in claim 1 further comprising determining a steering wheel angle, wherein applying brake-steer comprises applying brake-steer as a function of hand wheel torque and steering wheel angle.

3. A method as recited in claim 1 further comprising determining a steering wheel angle direction, wherein applying brake-steer comprises applying brake-steer as a function of hand wheel torque, steering wheel direction and steering wheel angle.

4. A method as recited in claim 1 wherein the steering wheel direction comprises an increasing direction and a decreasing direction wherein applying brake-steer comprises applying brake-steer using a first boost curve in the first direction applying brake-steer using a second boost curve in the second direction wherein the first boost curve is different than the second boost curve.

5. A method as recited in claim 4 wherein the first boost curve comprises a non-linear-boost curve.

6. A method as recited in claim 4 wherein the first boost curve increases brake-steer at a first rate for a first period of time, increases brake-steer at a second rate for a second period of time, wherein the second rate is greater than the first rate and increases brake-steer at a third rate for a third period of time wherein the third rate is less than the second rate.

7. A method as recited in claim 4 wherein the second boost curve comprises a non-linear-boost curve.

8. A method as recited in claim 4 wherein the second boost curve decreases brake-steer at a first rate for a first period of time, decreases brake-steer at a second rate for a second period of time, wherein the second rate is less than the first rate.

9. A method as recited in claim 1 further comprising prior to applying brake-steer, comparing the steering wheel torque to a predetermined torque and when the steering torque is greater than the predetermined torque, performing the step of applying brake-steer, and when the steering wheel torque is below the predetermined torque not applying brake-steer.

10. A method as recited in claim 9 wherein the torque comprises an increasing torque and a decreasing torque and wherein applying brake-steer comprises applying brake-steer using a first boost curve during increasing torque and applying brake-steer using a second boost curve during decreasing torque wherein the first boost curve is different than the second boost curve.

11. A method as recited in claim 10 wherein the first boost curve comprises a non-linear-boost curve.

12. A method as recited in claim 10 wherein the first boost curve increases brake-steer at a first rate for a first period of time, increases brake-steer at a second rate for a second period of time, wherein the second rate is greater than the first rate, and increases brake-steer at third rate for a third period of time wherein the third rate is less than the second rate.

13. A method as recited in claim 10 wherein the second boost curve comprises a non-linear-boost curve.

14. A method as recited in claim 10 wherein the second boost curve decreases brake-steer at a first rate for a first period of time, decreases brake-steer at a second rate for a second period of time, wherein the second rate is less than the first rate.

15. A method as recited in claim 1 further comprising reducing the turning radius of the vehicle during applying brake-steer.

16. A method as recited in claim 1 wherein applying brake-steer comprises applying at least one brake at a first wheel to reduce a vehicle turning radius.

17. A method as recited in claim 1 wherein applying brake-steer comprises applying an increased drive torque to a second wheel.

18. A method as recited in claim 1 further comprising determining a speed wherein applying a brake-steer comprises applying brake-steer as a function of steering wheel torque and vehicle speed.

19. A control system for a vehicle comprising:

a steering torque sensor generating a steering torque signal; and

a controller applying brake-steer to a vehicle as a function of the steering torque signal.

20. A control system as recited in claim 19 wherein said controller applies brake-steer as a function of a vehicle speed.

21. A control system as recited in claim 19 wherein said controller applies a brake to apply brake-steer.

22. A control system as recited in claim 19 wherein said controller applies a differential torque steer.

23. A control system as recited in claim 19 wherein said controller changes to a 4×

2 mode from a 4×

4 mode to apply brake-steer.

24. A method of controlling an automotive vehicle having a steering actuator having a lock position, said method comprising:

turning a hand wheel in a first direction until the steering actuator is in the lock position; and

initiating brake-steer on the vehicle in response to torque applied to the hand wheel.

25. A method as recited in claim 24 wherein initiating brake-steer comprises controlling a first vehicle wheel speed.

26. A method as recited in claim 24 wherein controlling the first wheel speed comprises braking the first vehicle wheel.

27. A method as recited in claim 24 wherein controlling the first wheel speed comprises applying a predetermined positive torque to a second wheel while braking the first wheel.

28. A method as recited in claim 24 wherein controlling the first wheel speed comprises applying a predetermined torque to the first wheel.

29. A method as recited in claim 24 wherein controlling the first wheel speed comprises applying a first predetermined torque to the first wheel and a second predetermined torque to a second wheel, said second predetermined torque greater than the first predetermined torque.

30. A method as recited in claim 29 wherein the first predetermined torque comprises a positive torque.

31. A method as recited in claim 29 wherein the first predetermined torque comprises a negative torque.

32. A method as recited in claim 24 further comprising determining a lock position in response to a pressure in a steering system.

33. A method as recited in claim 24 further comprising determining a lock position by measuring a relief pressure.

34. A method of controlling an automotive vehicle comprising:

generating a first wheel speed signal;

generating a second wheel speed signal;

generating a third wheel speed signal;

generating a desired wheel speed for the first wheel based on the second wheel speed signal, the third wheel speed signal and the fourth wheel speed signal; and

controlling the first wheel speed to the desired wheel speed to reduce a turning radius of the vehicle.

35. A method as recited in claim 34 further comprising generating a fourth wheel speed signal and wherein generating comprises generating a desired wheel speed for the first wheel based on the second wheel speed signal, the third wheel speed signal and the fourth wheel speed signal.

36. A method as recited in claim 34 wherein controlling the first wheel speed comprises braking the first wheel.

37. A method as recited in claim 34 wherein controlling the first wheel speed comprises applying a predetermined torque to the wheel.

38. A method as recited in claim 37 wherein the predetermined torque comprises a positive torque.

39. A method as recited in claim 37 wherein the predetermined torque comprises a negative torque.

40. A method as recited in claim 34 wherein generating a desired wheel speed comprises generating the desired wheel speed in response to a traction control system.

41. A method as recited in claim 34 wherein generating a desired wheel speed comprises generating the desired wheel speed in response to an anti-lock brake system.