Tire side slip angle control for an automotive vehicle using steering actuators

• US 6,662,898 B1
• Filed: 10/16/2002
• Issued: 12/16/2003
• Est. Priority Date: 10/16/2002
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Mattson, Keith Glenn, Brown, Todd Allen
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): WINNER, TONY H
• Application Number:
  US10/065,424
• Time in Patent Office: 426 Days
• Field of Search: 180/402, 180/443, 180/446, 701/41, 701/42, 280/5.51
• US Class Current: 180/446
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 2400/0521 Roll rate
• CPC Class Codes: B60G 2400/0522 Pitch rate
• CPC Class Codes: B60G 2400/0523 Yaw rate
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/412 of steering wheel or column
• CPC Class Codes: B60G 2400/822 Road friction coefficient determination affecting wheel traction
• CPC Class Codes: B60G 2800/212 Transversal; Side-slip during cornering
• CPC Class Codes: B60G 2800/215 by applying a braking action on each wheel individually
• CPC Class Codes: B60G 2800/244 Oversteer
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/92 ABS - Brake Control
• CPC Class Codes: B60G 2800/96 ASC - Assisted or power Steering control
• CPC Class Codes: B60T 2260/022 Rear-wheel steering; Four-wheel steering
• CPC Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel

Abstract

A stability control system (24) for an automotive vehicle includes a plurality of sensors sensing the dynamic conditions of the vehicle. The controller (26) is coupled to the sensors. The controller (26) determines a road surface coefficient of friction, calculates a maximum slip angle based on the road surface coefficient of friction, determines a calculated side slip angle in response to measured dynamic vehicle conditions, and reduces a steering wheel actuator angle when the calculated side slip angle is greater than the maximum slip angle.

Claims

1. A control system for an automotive vehicle having a steering actuator comprising:

a plurality of sensors generating a plurality of signals corresponding to measured dynamic vehicle conditions; and

a controller coupled to the plurality of sensors, said controller determines a road surface coefficient of friction, calculates a maximum permissible slip angle based on the road surface coefficient of friction, determines a calculated side slip angle in response to measured dynamic vehicle conditions, and reduces a steering wheel actuator angle when the calculated side slip angle is greater than the maximum slip angle.

2. A system as recited in claim 1 wherein said steering actuator comprises a front right wheel actuator and a front left wheel actuator.

3. A system as recited in claim 2 wherein said front right wheel steering actuator and said front left steering actuator are independently controllable.

4. A system as recited in claim 3 wherein said controller generates a front right control signal and a front left control signal in reducing the steering wheel actuator angle.

5. A system as recited in claim 1 wherein said steering actuator comprises a rear steering actuator and a front steering actuator.

6. A system as recited in claim 1 wherein said controller determines a rear steering control signal in reducing the steering wheel actuator angle.

7. A method of controlling a vehicle having a steering actuator comprising:

determining a road surface coefficient of friction;

calculating a maximum permissible slip angle based on the road surface coefficient of friction;

determining a calculated side slip angle in response to measured dynamic vehicle conditions; and

reducing a steering wheel actuator angle when the calculated side slip angle is greater than the maximum permissible slip angle.

8. A method as recited in claim 7 wherein reducing comprises reducing a steering wheel actuator angle when the calculated side slip angle is greater that the maximum slip angle until the calculated side slip angle is substantially equal to the maximum slip angle.

9. A method as recited in claim 7 wherein reducing comprises reducing a steering wheel actuator angle independent from a steering hand wheel when the calculated side slip angle is greater that the maximum permissible slip angle.

10. A method as recited in claim 7 wherein determining a calculated side slip angle in response to measured dynamic vehicle conditions comprises measuring a lateral acceleration, wheel speed, yaw rate and steering wheel angle.

11. A method as recited in claim 7 wherein the maximum slip angle is greater than a peak slip angle.

12. A method as recited in claim 7 wherein reducing a steering wheel actuator angle is performed independent of the handwheel position.

13. A method as recited in claim 7 wherein reducing a steering wheel actuator angle is performed in addition to the handwheel position.

14. A method as recited in claim 7 wherein reducing a steering wheel actuator angle when the calculated side slip angle is greater that the maximum slip angle comprises controlling a front steering actuator.

15. A method as recited in claim 7 wherein reducing a steering wheel actuator angle when the calculated side slip angle is greater that the maximum slip angle comprises controlling a rear steering actuator.

16. A method as recited in claim 7 wherein reducing a steering wheel actuator angle when the calculated side slip angle is greater that the maximum slip angle comprises controlling a front right steering actuator.

17. A method as recited in claim 7 wherein reducing a steering wheel actuator angle when the calculated side slip angle is greater that the maximum slip angle comprises controlling a front left steering actuator.

18. A method of controlling a vehicle having a steering actuator comprising:

determining a road surface coefficient of friction;

calculating a maximum permissible slip angle and a peak slip angle based on the road surface coefficient of friction;

determining a calculated side slip angle in response to measured vehicle conditions; and

controlling a steering wheel actuator angle to maintain the calculated side slip angle between the peak side slip angle and the maximum permissible slip angle.

19. A method as recited in claim 18 wherein the maximum permissible slip angle is greater than the peak slip angle.

20. A method as recited in claim 18 wherein controlling a steering wheel actuator angle comprises reducing the steering wheel actuation angle when the steering angle is less than the peak slip angle.