Method for Determining Estimated Vehicle Dynamics Parameters

• US 20070276564A1
• Filed: 08/13/2007
• Published: 11/29/2007
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Shin, Kwang-Keun, Chin, Yuen-Kwok
• Granted Patent: US 7,487,021 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B60W 2050/0028 Mathematical models, e.g. for simulation
• CPC Class Codes: B60W 2510/20 Steering systems
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/045 Improving turning performance
• CPC Class Codes: B60W 40/12 related to parameters of the vehicle itself , e.g. tyre models
• CPC Class Codes: B62D 6/007 adjustable by the driver, e.g. sport mode

Abstract

A method for determining estimated vehicle dynamics parameters using a vehicle parameter estimator, a vehicle condition detector and a rich steering input detector for estimating vehicle understeer coefficient and front and rear cornering compliances in real time. The vehicle parameter estimator receives a front wheel steering angle signal, a rear wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal, and employs a linear parameter estimation algorithm for estimating the understeer coefficient, and the front and rear corning compliance. The vehicle condition detector receives the front wheel steering angle signal, the rear wheel steering angle signal, the vehicle yaw rate signal and the vehicle speed signal, and disables the vehicle parameter estimator if the vehicle is not operating in a linear region. The rich steering input detector determines whether the estimated vehicle parameters are reliable and are ready to be used.

Claims

1. A method for determining estimated vehicle dynamics parameters, said method comprising:

estimating the vehicle parameters using input signals including a front wheel steering angle signal, a rear wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal, wherein estimating the vehicle parameters includes using a linear parameter estimation algorithm;

disabling the vehicle dynamics parameter estimation if the vehicle is not operating in a linear region; and

disregarding the estimated vehicle parameters if a rich steering input condition is not met and the estimated vehicle parameters are not reliable and are not ready to be used.

2. The method according to claim 1 wherein estimating the vehicle parameters includes estimating a vehicle understeer coefficient, a front comering compliance and a rear cornering compliance.

3. The method according to claim 1 wherein estimating the vehicle parameters includes converting the input signals to converted values, executing the linear parameter estimation algorithm based on the converted values to generate estimation values, and calculating the vehicle parameters based on the estimation values.

4. The method according to claim 3 wherein converting the input signals to converted values includes filtering the signals, integrating the signals and generating regression vectors.

5. The method according to claim 1 wherein disabling the estimated vehicle parameters if the vehicle is not operating in a linear region includes disabling the estimated vehicle parameters if the vehicle is not traveling faster than a predetermined speed, the vehicle is accelerating or decelerating faster than a predetermined rate or the vehicle yaw rate is greater than a predetermined yaw rate.

6. The method according to claim 5 wherein determining if the vehicle yaw rate is greater than a predetermined yaw rate includes comparing the vehicle yaw rate to a reference yaw rate.

7. The method according to claim 1 wherein estimating the vehicle parameters includes determining if a steady state turning condition is met.

8. The method according to claim 1 wherein estimating the vehicle parameters includes using an algorithm selected from the group consisting of recursive least squares algorithms and Lyapunov-based algorithms.

9. The method according to claim 1 wherein disregarding the estimated vehicle parameters includes determining a reference model that has pre-defined reference model parameters, providing an estimation of the reference model parameters and comparing the estimation of the reference model parameters to the pre-defined reference model parameters.

10. A method for determining estimated vehicle dynamics parameters, said method comprising:

estimating vehicle understeer coefficient, front cornering compliance and rear-comering compliance using a linear parameter estimation algorithm; and

disregarding the estimation of the vehicle understeer coefficient, the front cornering compliance and the rear-cornering compliance if the vehicle is not operating in a linear region.

11. The method according to claim 10 wherein estimating the vehicle parameters includes using a front wheel steering angle signal, a rear wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal, and determining whether the vehicle is operating in the linear region includes using the front wheel steering angle signal, the rear wheel steering angle signal, the vehicle yaw rate signal and the vehicle speed signal.

12. The method according to claim 10 wherein estimating the vehicle parameters includes converting input signals to parameter estimator converted values, executing the linear parameter estimation algorithm based on the converted values to generate estimation values, and calculating the understeer coefficient, the front cornering compliance and the rear cornering compliance based on the estimation values.

13. The method according to claim 10 wherein determining whether the vehicle is operating in a linear region includes determining whether the vehicle is traveling faster than a predetermined speed, whether the vehicle is accelerating or decelerating faster than a predetermined rate or whether the vehicle yaw rate is greater than a predetermined yaw rate.

14. The method according to claim 13 wherein determining if the vehicle is operating in a linear region includes determining that the vehicle yaw rate is greater than a predetermined yaw rate by comparing the vehicle yaw rate to a reference yaw rate.

15. The method according to claim 10 further comprising determining whether the estimated parameters are reliable enough.

16. The method according to claim 15 wherein determining if the estimated vehicle parameters are reliable enough includes determining a reference understeer coefficient, a reference front cornering compliance and a reference rear cornering compliance of a reference model, providing an estimation of the understeer coefficient, the front cornering compliance and the rear cornering compliance of the reference model, and comparing the reference understeer coefficient, the reference front cornering compliance and the reference rear cornering compliance of the reference model to the estimated understeer coefficient, the estimated front cornering compliance and the estimated rear cornering compliance of the reference model.

17. A method for determining estimated vehicle dynamics parameters, said method comprising:

estimating a vehicle understeer coefficient, a front cornering compliance and a rear cornering compliance using a linear parameter estimation algorithm and input signals including a front wheel steering angle signal, a rear wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal;

disabling the vehicle dynamics parameter estimation if the vehicle is not traveling faster than a predetermined speed, the vehicle is accelerating or decelerating faster than a predetermined rate or the vehicle yaw rate is greater than a predetermined yaw rate; and

disregarding the estimated vehicle parameters if a rich steering input condition is not met and the estimated vehicle parameters are not reliable and are not ready to be used, wherein disregarding the estimated vehicle parameters includes determining a reference model that has pre-defined reference model parameters, providing an estimation of the reference model parameters and comparing the estimation of the reference model parameters to the pre-defined reference model parameters.

18. The method according to claim 17 wherein estimating the vehicle parameters includes converting the input signals to converted values, executing the linear parameter estimation algorithm based on the converted values to generate estimation values, and calculating the vehicle parameters based on the estimation values.

19. The method according to claim 18 wherein converting the input signals to converted values includes filtering the signals, integrating the signals and generating regression vectors.

20. The method according to claim 17 wherein estimating the vehicle parameters includes determining if a steady state turning condition is met.