Handwheel damping control of active steering system

• US 7,546,191 B2
• Filed: 12/20/2004
• Issued: 06/09/2009
• Est. Priority Date: 12/20/2004
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Bolio, Robert R., Lin, William C., Chen, Shih-Ken
• Primary Examiner(s): Keith; Jack W
• Assistant Examiner(s): Diacou; Ari M
• Application Number:
  US11/017,420
• Publication Number:
  US 20060136108A1
• Time in Patent Office: 1,632 Days
• Field of Search: None
• US Class Current: 701/42
• CPC Class Codes: B62D 5/008 Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

An active front steering (AFS) system that provides hand-wheel damping. The AFS system includes a damping control sub-system that determines a hand-wheel angular velocity based on the rate of change of a hand-wheel angle signal. The damping control sub-system determines the damping control signal by multiplying the angular velocity of the hand-wheel angle signal with a control gain. The damping control signal is added to a steering signal from a variable gear ratio control sub-system to generate a steering command signal. The damping control sub-system sets to the damping control signal to zero if a signal from a vehicle stability enhancement sub-system is activated.

Claims

1. A method for providing active front steering for a vehicle that includes hand-wheel damping control, said method comprising:

providing a vehicle speed signal of the speed of the vehicle;

providing a hand-wheel steering angle signal indicative of the vehicle operator'"'"'s desired steering direction;

generating a damping control signal using the vehicle speed signal and the steering angle signal; and

apply the damping control signal to a controller that controls the steering of the vehicle, said damping control signal providing the hand-wheel damping control.

2. The method according to claim 1 further comprising adding the damping control signal to a variable gear ratio control signal to generate a steering command signal applied to the controller.

3. The method according to claim 1 further comprising setting the damping control signal to zero if a closed-loop stability enhancement signal is activated.

4. The method according to claim 1 wherein the damping control gain based on the vehicle speed and the damping control based on the hand-wheel angle are provided by look-up tables.

5. The method according to claim 1 wherein providing a steering angle signal includes using a hand-wheel angle sensor mounted to a steering column of the vehicle.

6. The method according to claim 1 wherein the controller is an actuator controller that controls an actuator that provides the vehicle steering.

7. An active front steering system for a vehicle, said system comprising:

a vehicle speed sensor for providing a vehicle speed signal of the speed of the vehicle;

a steering angle sensor providing a steering angle signal indicative of the vehicle operator'"'"'s desired steering direction;

a damping control sub-system responsive to the vehicle speed signal and the steering angle signal, said damping control sub-system generating a damping control signal for providing vehicle hand-wheel damping; and

a controller responsive to the damping control signal, said controller controlling an actuator that controls the steering of the vehicle.

8. The system according to claim 7 wherein the damping control sub-system generates the damping control gain by multiplying a damping control gain based on vehicle speed with a damping control gain based on the steering angle signal.

9. The system according to claim 8 wherein the damping control sub-system uses look-up tables for providing the damping control gain based on vehicle speed and the damping control gain based on the steering angle signal.

10. The system according to claim 7 further comprising a variable gear ratio control sub-system, said variable gear ratio control sub-system generating a steering command based on the vehicle speed signal and the steering angle signal, wherein the steering command is added to the damping control signal to generate a steering command signal applied to the controller.

11. The system according to claim 7 further comprising a closed-loop stability enhancement sub-system, said closed-loop stability enhancement sub-system providing a stability enhancement signal, wherein the damping control signal is set to zero if the stability enhancement signal is activated.

12. The system according to claim 7 wherein the steering angle sensor is a hand-wheel angle sensor mounted to a steering column of the vehicle.