Integrating active front steering and vehicle stability brake control

• US 20050149243A1
• Filed: 01/06/2004
• Published: 07/07/2005
• Est. Priority Date: 01/06/2004
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Ghoneim, Youssef A.
• Granted Patent: US 7,698,034 B2
• Time in Patent Office: Days
• US Class Current: 701/48
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• 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 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 30/025 related to comfort of drivers or passengers
• CPC Class Codes: B60W 40/11 Pitch movement
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence

Abstract

An integrated vehicle control system includes a first control system having a maximum authority to selectively operate a first vehicle sub-system and a second control system to selectively operate a second vehicle sub-system. A controller is adapted to monitor a first parameter associated with the first vehicle sub-system and a second parameter associated with the second vehicle sub-system. The controller is operable to control the first and second parameters by selectively invoking operation of the second control system when the first control system exceeds the maximum authority and the second parameter exceeds an upper threshold.

Claims

1. An integrated vehicle control system, comprising:

a first control system having a maximum authority to selectively operate a first vehicle sub-system;

a second control system to selectively operate a second vehicle sub-system; and

a controller adapted to monitor a first parameter associated with said first vehicle sub-system and a second parameter associated with said second vehicle sub-system, said controller being operable to control said first and second parameters by selectively invoke operation of said second control system when said first control system exceeds said maximum authority and said second parameter exceeds an upper threshold.

2. The integrated vehicle control system of claim 1 wherein said first parameter is a steering angle and said first control system includes a steering system that generates a steering angle command based on a steering angle input.

3. The integrated vehicle control system of claim 2 further comprising a steering angle sensor that measures a vehicle steering angle.

4. The integrated vehicle control system of claim 3 wherein said first control sub-system exceeds said maximum authority if said steering angle command exceeds a steering angle threshold.

5. The integrated vehicle control system of claim 1 wherein said second control system includes a vehicle stability enhancement system.

6. The integrated vehicle control system of claim 5 further comprising a sensor that generates a signal indicative of said second parameter.

7. The integrated vehicle control system of claim 6 wherein said sensor includes one of a yaw rate sensor that measures a vehicle yaw rate and a lateral accelerometer that measures a vehicle lateral acceleration.

8. The integrated vehicle control system of claim 1 wherein said second vehicle parameter includes one of a yaw rate error and a yaw rate error acceleration.

9. The integrated vehicle control system of claim 8 wherein said yaw rate error is a difference between a yaw rate measured by said a sensor and a yaw rate command generated by said controller.

10. The integrated vehicle control system of claim 9 wherein said controller invokes operation of said second control system when one of said yaw rate error exceeds a yaw rate error upper threshold and said yaw rate error acceleration exceeds a yaw rate error acceleration upper threshold.

11. The integrated vehicle control system of claim 10 wherein said controller segregates operation of said first and second control systems when one of said yaw rate error is less than a yaw rate error lower threshold and said yaw rate error acceleration is less than a yaw rate error acceleration lower threshold for a threshold period.

12. The integrated vehicle control system of claim 8 wherein said second vehicle parameter further includes a velocity and a lateral velocity rate.

13. The integrated vehicle control system of claim 12 wherein said controller invokes operation of said first and second control systems when said velocity exceeds a velocity threshold and said lateral velocity rate exceeds a lateral velocity rate threshold.

14. The integrated vehicle control system of claim 1 wherein said controller segregates operation of said first and second control systems if said second vehicle parameter is less than a lower threshold for a threshold period.

15. A method of integrating control sub-systems of a vehicle, comprising:

operating a first control sub-system to control a first set of vehicle parameters;

determining whether said first control sub-system has achieved a maximum authority in controlling said first set of vehicle parameters;

determining whether a second set of vehicle parameters exceed respective upper thresholds; and

operating a second control sub-system to control said second set of vehicle parameters when said second set of vehicle parameters exceed said respective upper thresholds.

16. The method of claim 15 further comprising operating said first control sub-system concurrently with said second control sub-system to control said first set of vehicle parameters when said second set of vehicle parameters exceed said respective upper thresholds.

17. The method of claim 15 further comprising:

comparing at least one of said second set of vehicle parameters to a respective lower threshold; and

terminating operation of said second control sub-system if said at least one of said second vehicle parameters is below said respective lower threshold.

18. The method of claim 16 further comprising:

comparing at least one of said second set of vehicle parameters to a respective lower threshold for a threshold time period after said step of terminating operation of said second control sub-system; and

operating said first control sub-system when at least one of said second set of vehicle parameters is lower than said respective lower threshold for said threshold time period.

19. The method of claim 15 wherein said first control sub-system is an active front steering (AFS) system and said first set of vehicle parameters includes a steering angle.

20. The method of claim 19 wherein said first control sub-system has achieved said maximum authority if a steering angle correction generated by said first control sub-system exceeds a steering angle correction threshold.

21. The method of claim 15 wherein said second control sub-system is a vehicle stability enhancement (VSE) system.

22. The method of claim 21 wherein said second set of vehicle parameters include a yaw rate error, a yaw rate error acceleration, a vehicle velocity and a vehicle lateral velocity rate.

23. The method of claim 22 wherein said step of determining whether a second set of vehicle parameters exceed respective thresholds comprises:

comparing said yaw rate error to a yaw rate error upper threshold;

comparing said yaw rate error acceleration to a yaw rate error acceleration upper threshold;

comparing said vehicle velocity to a vehicle velocity threshold; and

comparing said vehicle lateral velocity rate to a vehicle lateral velocity rate threshold.

24. The method of claim 23 wherein said step of operating a second control sub-system to control said second set of vehicle parameters occurs when one of said yaw rate error exceeds said yaw rate error upper threshold and said yaw rate error acceleration exceeds said yaw rate error acceleration upper threshold.

25. The method of claim 23 wherein said step of operating a second control sub-system to control said second set of vehicle parameters occurs when said vehicle velocity exceeds said vehicle velocity threshold and said vehicle lateral velocity rate exceeds said vehicle lateral velocity rate threshold.

26. A vehicle having an integrated vehicle control system, comprising:

a first control system that selectively operates a steering system;

a second control system that selectively operates a vehicle drivetrain;

a controller adapted to monitor a first parameter associated with said steering system, said controller being operable to selectively invoke operation of said second control system when said first control system exceeds a threshold.

27. The vehicle of claim 26 wherein said controller is adapted to monitor a second parameter associated with said vehicle drivetrain and wherein said controller selectively invokes operation of said second control system when said second parameter exceeds an upper threshold.

28. The vehicle of claim 27 wherein said controller compares said second parameter to a lower threshold and terminates operation of said second control system if said second vehicle parameter is below said lower threshold.

29. The vehicle of claim 27 wherein said controller compares said second parameter to a lower threshold for a threshold time period after said step of terminating operation of said second control system and operates said first control system only if said second parameter is lower than said lower threshold for said threshold time period.

30. The vehicle of claim 26 wherein said first parameter includes a steering angle.

31. The vehicle of claim 30 wherein said first control system exceeds said threshold when a steering angle correction generated by said first control system exceeds a steering angle correction threshold.

32. The vehicle of claim 26 wherein said second control system is a vehicle stability enhancement (VSE) system that controls a second parameter.

33. The vehicle of claim 32 wherein said second parameter includes at least one of a yaw rate error, a yaw rate error acceleration, a vehicle velocity and a vehicle lateral velocity rate.

34. The vehicle of claim 33 further comprising a yaw rate sensor that measures a yaw rate, wherein said yaw rate error is a difference between said measured yaw rate and a yaw rate command generated by said controller.

35. The vehicle of claim 34 further comprising:

a plurality of road wheels; and

a plurality of brakes associated with said road wheels, wherein said VSE system actuates braking of said road wheels to achieve said yaw rate command.

36. The vehicle of claim 35 further comprising an engine, wherein said VSE system manipulates a torque output of said engine to achieve said yaw rate command.

37. The vehicle of claim 33 wherein said controller compares said yaw rate error to a yaw rate error upper threshold, compares said yaw rate error acceleration to a yaw rate error acceleration upper threshold, compares said vehicle velocity to a vehicle velocity threshold and compares said vehicle lateral velocity rate to a vehicle lateral velocity rate threshold.

38. The vehicle of claim 37 wherein said controller operates said second control system to control said second parameter if one of said yaw rate error exceeds said yaw rate error upper threshold and said yaw rate error acceleration exceeds said yaw rate error acceleration upper threshold.

39. The vehicle of claim 37 wherein said controller operates said second control system to control said second parameter if said vehicle velocity exceeds said vehicle velocity threshold and said vehicle lateral velocity rate exceeds said vehicle lateral velocity rate threshold.