Method and system for adaptively compensating closed-loop front-wheel steering control

• US 20070213902A1
• Filed: 03/10/2006
• Published: 09/13/2007
• Est. Priority Date: 03/10/2006
• 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: Shin, Kwang-Keun, Chen, Shih-Ken
• Granted Patent: US 7,599,774 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B62D 6/007 adjustable by the driver, e.g. sport mode

Abstract

An active front-wheel vehicle steering control system that employs closed-loop control includes an adaptive compensation sub-system that compensates for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated front cornering compliance and rear cornering compliance based on a steering wheel angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. The closed-loop control includes active gain for each of vehicle yaw rate, yaw acceleration, side-slip and side-slip rate, all based on the vehicle speed and vehicle dynamic parameter changes for use in generating a steering angle control signal to the front wheels of the vehicle.

Claims

1. Closed-loop control system providing a steering control signal for front wheels of a vehicle, said system comprising:

a vehicle dynamics parameter estimation sub-system providing difference signals indicative of change between estimated and nominal vehicle dynamics parameters;

a closed-loop adaptive compensation sub-system providing

at least one of nominal yaw rate, yaw acceleration signal, side-slip signal and side-slip rate signals,

and respective corresponding at least one of corrected yaw rate, yaw acceleration, side-slip and side-slip rate signals; and

said steering control signal based on said at least one of said nominal signals and said respective corresponding at least one of said corrected signals.

2. Control system for providing active front-wheel steering for a vehicle, said system comprising:

a vehicle dynamics parameter estimation sub-system responsive to input signals, said vehicle dynamics parameter estimation sub-system employing a parameter estimation algorithm for estimating vehicle parameters based on the input signals, said vehicle dynamics parameter estimation sub-system comparing the estimated vehicle parameters with nominal vehicle parameters and generating difference signals indicative of the change between the estimated vehicle dynamics parameters and the nominal vehicle dynamics parameters; and

a closed-loop control sub-system being responsive to the vehicle speed signal and the input signals applied to the vehicle dynamics parameter estimation sub-system for generating a closed-loop steering control signal to the front wheels of the vehicle, said closed-loop control sub-system including at least one look-up table providing a nominal closed-loop steering angle signal and at least one closed-loop adaptive compensation sub-system providing a corrected closed-loop steering angle signal, said closed-loop steering control signal comprising a combination of the nominal closed-loop steering angle signal and the corrected closed-loop steering angle signal.

3. The system according to claim 2 wherein the at least one closed-loop look-up table and the at least one closed-loop adaptive compensation sub-system include a yaw rate feedback look-up table and a yaw rate feedback adaptive compensation sub-system, said yaw rate feedback look-up table providing an original yaw rate feedback angle signal and said yaw rate feedback adaptive compensation sub-system providing a corrected yaw rate feedback angle signal based on the estimated vehicle dynamics parameters.

4. The system according to claim 3 wherein the yaw rate feedback adaptive compensation sub-system generates the corrected yaw rate feedback angle signal in accordance with the relationship:

5. The system according to claim 2 wherein the at least one closed-loop look-up table and the at least one closed-loop adaptive compensation sub-system include a yaw acceleration feedback look-up table and a yaw acceleration feedback adaptive compensation sub-system, said yaw acceleration feedback look-up table providing an original yaw acceleration feedback angle signal and said yaw acceleration feedback adaptive compensation sub-system providing a corrected yaw acceleration feedback angle signal based on the estimated vehicle dynamics parameters.

6. The system according to claim 5 wherein the yaw acceleration feedback compensation sub-system generates the corrected yaw acceleration feedback angle in accordance with the relationship:

7. The system according to claim 2 wherein the at least one closed-loop look-up table and the at least one closed-loop adaptive compensation sub-system include a side-slip feedback look-up table and a side-slip feedback adaptive compensation sub-system, said side-slip feedback look-up table providing an original side-slip feedback angle signal and said side-slip feedback adaptive compensation sub-system providing a corrected side-slip feedback angle signal based on the estimated vehicle dynamics parameters.

8. The system according to claim 7 wherein the side-slip feedback adaptive compensation sub-system generates the corrected side-slip feedback angle signal in accordance with the relationship:

9. The system according to claim 2 wherein the at least one closed-loop look-up table and the at least one closed-loop adaptive compensation sub-system include a side-slip rate feedback look-up table and a side-slip rate feedback adaptive compensation sub-system, said side-slip rate feedback look-up table providing an original side-slip rate feedback angle signal and said side-slip rate feedback adaptive compensation sub-system providing a corrected side-slip rate feedback angle signal based on the estimated vehicle dynamics parameters.

10. The system according to claim 9 wherein the side-slip rate feedback adaptive compensation sub-system generates the corrected side-slip rate feedback angle in accordance with the relationship:

11. The system according to claim 2 wherein the vehicle dynamics parameter estimation sub-system receives a steering wheel angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and the vehicle speed signal as the input signals.

12. Control system for providing active front-wheel steering for a vehicle, said system comprising:

a vehicle dynamics parameter estimation sub-system responsive to input signals including a front-wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and the vehicle speed signal, said vehicle dynamics parameter estimation sub-system employing a linear parameter estimation algorithm for estimating vehicle parameters based on the input signals, said vehicle dynamics parameter estimation system comparing the estimated vehicle parameters with nominal vehicle parameters and generating difference signals indicative of the change between the estimated vehicle dynamics parameters and the nominal vehicle dynamic parameters; and

a closed-loop control sub-system being responsive to the vehicle speed signal and the input signals applied to the vehicle dynamics parameter estimation sub-system for generating a closed-loop steering control signal to the front wheels of the vehicle, said closed-loop sub-system including include a yaw rate feedback look-up table and a yaw rate feedback adaptive compensation sub-system, said yaw rate feedback look-up table providing an original yaw rate feedback angle signal and said yaw rate feedback adaptive compensation sub-system providing a corrected yaw rate feedback angle signal based on the estimated vehicle dynamics parameters, said closed-loop sub-system further including a yaw acceleration feedback look-up table and a yaw acceleration feedback adaptive compensation sub-system, said yaw acceleration feedback look-up table providing an original yaw acceleration feedback angle signal and said yaw acceleration feedback adaptive compensation sub-system providing a corrected yaw acceleration feedback angle signal based on the estimated vehicle dynamics parameters, said closed-loop sub-system further including a side-slip feedback look-up table and a side-slip feedback adaptive compensation sub-system, said side-slip feedback look-up table providing an original side-slip feedback angle signal and said side-slip feedback adaptive compensation sub-system providing a corrected side-slip feedback angle signal based on the estimated vehicle dynamics parameters and said closed-loop sub-system further including a side-slip rate feedback look-up table and a side-slip rate feedback adaptive compensation sub-system, said side-slip rate feedback look-up table providing an original side-slip rate feedback angle signal and said side-slip rate feedback adaptive compensation sub-system providing a corrected side-slip rate feedback angle signal based on the estimated vehicle dynamics parameters, wherein said closed-loop steering control signal comprises the original yaw rate feedback angle signal, the corrected yaw rate feedback angle signal, the original yaw acceleration feedback angle signal, the corrected yaw acceleration feedback angle signal, the original side-slip feedback angle signal, the corrected side-slip feedback angle signal and the original side-slip rate feedback angle signal.

13. Method for providing active front-wheel steering for a vehicle, said method comprising:

receiving vehicle input signals, including vehicle speed;

estimating vehicle parameters based on the input signals, comparing the estimated vehicle parameters with nominal vehicle parameters and generating difference signals indicative of the change between the estimated vehicle dynamics parameters and the nominal vehicle dynamic parameters; and

generating a nominal closed-loop steering angle signal based on the input signals and the nominal vehicle parameters;

generating a corrected closed-loop steering angle signal based on the vehicle input signals and the difference signals; and

generating a closed-loop steering angle control signal to the front wheels of the vehicle based on the nominal closed-loop steering angle signal and the corrected closed-loop steering angle signal.

14. The method according to claim 13 wherein generating the nominal closed-loop steering angle signal includes generating an original yaw rate feedback angle signal and wherein generating the corrected closed-loop steering angle signal includes generating a corrected yaw rate feedback angle signal in accordance with the relationship:

15. The method according to claim 13 wherein generating the nominal closed-loop steering angle signal includes generating an original yaw acceleration feedback angle signal and wherein generating the corrected closed-loop steering angle signal includes generating a corrected yaw acceleration feedback angle signal in accordance with the relationship:

16. The method according to claim 13 wherein generating the nominal closed-loop steering angle signal includes generating an original side-slip feedback angle signal and wherein generating the corrected closed-loop steering angle signal includes generating a corrected side-slip feedback angle signal in accordance with the relationship:

17. The method according to claim 13 wherein generating the nominal closed-loop steering angle signal includes generating an original side-slip rate feedback angle signal and wherein generating the corrected closed-loop steering angle signal includes generating a corrected side-slip rate feedback angle signal in accordance with the relationship:

18. The method according to claim 13 wherein receiving the vehicle input signals includes receiving a steering wheel angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and the vehicle speed signal as the input signals.