ELECTRIC POWER STEERING CONTROL METHODS AND SYSTEMS

• US 20120209473A1
• Filed: 01/12/2012
• Published: 08/16/2012
• Est. Priority Date: 02/16/2011
• Status: Active Grant

• Current Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Nexteer beijing Technology Co Ltd
• Inventors: Birsching, Joel E., Chandy, Ashok
• Granted Patent: US 8,489,282 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input

Abstract

A control system for controlling a steering system is provided. The control system includes a first module that determines a hysteresis position based on handwheel velocity and handwheel torque. A second module selectively determines an assist curve based on the hysteresis position. A third module generates a final assist command based on the assist curve.

Claims

1. A control system for controlling a steering system, the control system comprising:

a first module that determines a hysteresis position based on handwheel velocity and handwheel torque;

a second module that selectively determines an assist curve based on the hysteresis position; and

a third module that generates a final assist command based on the assist curve.

2. The control system of claim 1, wherein the first module determines a direction of assist modification and the hysteresis position is determined based on the direction.

3. The control system of claim 2, wherein the first module determines the direction based on the handwheel torque when the handwheel velocity is below a first threshold.

4. The control system of claim 3, wherein the first module determines the direction based on handwheel velocity when the handwheel velocity is above a second threshold.

5. The control system of claim 4, wherein the module determines the direction based on a blending method when the handwheel velocity is between the first threshold and the second threshold.

6. The control system of claim 1, wherein the first module converts the handwheel velocity to a torque value.

7. The control system of claim 1, wherein the third module generates the final assist command based on at least one of an upper limit and a lower limit on the assist curve.

8. A method of controlling a steering system, the method comprising:

determining a hysteresis position based on handwheel velocity and handwheel torque;

selectively determining an assist curve based on the hysteresis position; and

generating a final assist command to the steering system based on the assist curve.

9. The method of claim 8, further comprising determining a direction of assist modification and the determining the hysteresis position is based on the direction.

10. The method of claim 9, wherein the determining the direction is based on the handwheel torque when the handwheel velocity is below a first threshold.

11. The method of claim 10, wherein determining the direction is based on handwheel velocity when the handwheel velocity is above a second threshold.

12. The method of claim 11, wherein determining the direction is based on a blending method when the handwheel velocity is between the first threshold and the second threshold.

13. The method of claim 8, further comprising converting the handwheel velocity to a torque value.

14. The method of claim 8, wherein generating the final assist command is based on at least one of an upper limit and a lower limit on the assist curve.

15. A system in a vehicle, comprising:

an electric power steering system; and

a control module that determines a hysteresis position based on handwheel velocity and handwheel torque, that selectively determines an assist curve based on the hysteresis position, and that generates a final assist command based on the assist curve.

16. The system of claim 15, wherein the first module determines a direction of assist modification and determines the hysteresis position based on the direction.

17. The system of claim 16, wherein the control module determines the direction based on the handwheel torque when the handwheel velocity is below a first threshold.

18. The system of claim 17, wherein the control module determines the direction based on handwheel velocity when the handwheel velocity is above a second threshold.

19. The system of claim 18, wherein the control module determines the direction based on a blending method when the handwheel velocity is between the first threshold and the second threshold.

20. The system of claim 15, wherein the control module converts the handwheel velocity to a torque value.