ELECTRIC POWER STEERING SYSTEMS WITH IMPROVED ROAD FEEL

• US 20120150389A1
• Filed: 12/14/2010
• Published: 06/14/2012
• Est. Priority Date: 12/14/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: OBLIZAJEK, KENNETH L., SOPOCI, JOHN D., PASTOR, STEPHEN R.
• Granted Patent: US 9,327,762 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B62D 5/0472 for damping vibrations

Abstract

A method is provided for controlling a motor drive torque in an EPS system having a motor and a steering assembly. The method includes receiving a torque signal from the steering assembly; processing the torque signal in accordance with a steering perception program to produce a motor control signal; and controlling the motor drive torque based on the motor control signal.

Claims

1. A method of controlling a motor drive torque in an electric power steering system having a motor and a steering assembly, the method comprising the steps of:

receiving a torque signal from the steering assembly;

processing the torque signal in accordance with a steering perception program to produce a motor control signal; and

controlling the motor drive torque based on the motor control signal.

2. The method of claim 1, further comprising applying a dithering signal to the motor control signal to produce a dithered motor control signal, and wherein the controlling step includes controlling the motor drive torque based on the dithered motor control signal.

3. The method of claim 2, wherein the applying step includes linearizing the motor control signal with the dithering signal to produce the dithered motor control signal.

4. The method of claim 2, further comprising the step of evaluating the torque signal and adjusting the dithering signal based on the torque signal.

5. The method of claim 4, wherein the adjusting step includes jointly considering the torque signal and the dithering signal.

6. The method of claim 4, wherein the processing step further includes processing the torque signal with a vibration attenuation program to produce a vibration attenuation signal as the motor control signal.

7. The method of claim 6, further comprising the steps of

determining an excitation from an external source based on the torque signal, and wherein the applying step includes generating the dithered motor control signal such that a first mechanical response to the dithering signal, the vibration attenuation signal and the excitation is approximately equal to that of a second mechanical response to the dithering signal when the excitation and torque attenuation signal are approximately zero.

8. The method of claim 6, further comprising evaluating the torque signal and selectively executing the vibration compensation program based on the torque signal.

9. The method of claim 1, wherein the step of executing the steering perception program includes applying friction models to the torque signal.

10. The method of claim 9, wherein the step of applying friction models includes applying LuGre'"'"' friction maps.

11. A system for controlling a motor drive torque for a vehicle having a motor and a steering assembly, the system comprising:

a sensor configured to at least facilitate obtaining a torque signal from the steering assembly; and

a processor coupled to the sensor and configured to at least facilitate;

receiving the torque signal from the sensor;

processing the torque signal in accordance with a steering perception program to produce a motor control signal; and

controlling the motor drive torque based on the motor control signal.

12. The system of claim 11, wherein the processor is further configured to apply a dithering signal to the motor control signal to produce a dithered motor control signal.

13. The system of claim 12, wherein the processor is configured to reduce the non-linearities of the steering system with the dithering signal to produce the dithered motor control signal.

14. The system of claim 12, wherein the processor is configured to evaluate the torque signal and adjust the dithering signal based on the torque signal.

15. The system of claim 12, wherein the processor is configured to apply vibration attenuation algorithms to the torque signal.

16. The system of claim 12, wherein the processor is configured to apply steering perception algorithms to the torque signal.

17. The system of claim 16, wherein the steering perception algorithms are friction models.

18. The system of claim 17, wherein the friction models are LuGre'"'"' friction maps.

19. A program product for controlling a motor drive torque for a vehicle having a motor and a steering assembly, the program product comprising:

a program configured to at least facilitate;

receiving a torque feedback signal from the steering assembly;

applying steering perception algorithms to the torque signal to generate a motor control signal; and

controlling the motor drive torque based on the motor control signal; and

a computer-readable signal bearing media bearing the program.

20. The program product of claim 19, wherein the program is configured to apply a dithering signal to the motor control signal.