STEERING COMPENSATION WITH GRIP SENSING

• US 20180093700A1
• Filed: 10/03/2016
• Published: 04/05/2018
• Est. Priority Date: 10/03/2016
• Status: Active Grant

• Current Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Inventors: Chandy, Ashok
• Granted Patent: US 10,399,591 B2
• Time in Patent Office: Days
• CPC Class Codes: B62D 1/043 with a device allowing single-hand operation of the steering wheel
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 6/10 characterised by means for sensing or determining torque

Abstract

A system for grip-based handwheel compensation includes a net handwheel torque moment determination module that determines a net handwheel torque moment between a left grip and a right grip on a handwheel. The system also includes a filter transition compensation module that applies a filter to smooth transitions in the net handwheel torque moment as a bias compensation. The system further includes a handwheel torque compensation module that determines a grip compensated handwheel torque based on a difference between a sensed handwheel torque and the bias compensation.

Claims

1. A system for grip-based handwheel compensation, the system comprising:

a net handwheel torque moment determination module that determines a net handwheel torque moment between a left grip and a right grip on a handwheel;

a filter transition compensation module that applies a filter to smooth transitions in the net handwheel torque moment as a bias compensation; and

a handwheel torque compensation module that determines a grip compensated handwheel torque based on a difference between a sensed handwheel torque and the bias compensation.

2. The system of claim 1, further comprising a scale one-handed module that determines a gain compensation to adjust a scaling of the grip compensated handwheel torque between a one-handed grip and a two-handed grip handwheel steering mode.

3. The system of claim 2, wherein the scale one-handed module determines that the one-handed grip handwheel steering mode is active based on a magnitude of the left grip or the right grip falling below a grip magnitude threshold.

4. The system of claim 3, wherein the gain compensation is a function of a lower value of the magnitude of the left grip and the right grip, and the gain compensation is filtered to smooth transitions in the scaling of the grip compensated handwheel torque.

5. The system of claim 1, wherein the net handwheel torque moment is determined based on a left grip angular position and a right grip angular position of the handwheel in reference to a straight ahead position.

6. The system of claim 5, wherein the net handwheel torque moment is further determined based on a left moment and a right moment in response to a nominal measure of arm weight and geometry of the left grip angular position, the right grip angular position, and the handwheel.

7. The system of claim 6, wherein the left moment is a product of a magnitude of the left grip and an offset based on the left grip angular position, and the right moment is a product of a magnitude of the right grip and an offset based on the right grip angular position.

8. A steering system comprising:

a handwheel torque sensor operable to produce a sensed handwheel torque;

a steering actuator motor; and

a control module operable to determine a net handwheel torque moment between a left grip and a right grip on a handwheel, apply a filter to smooth transitions in the net handwheel torque moment as a bias compensation, determine a grip compensated handwheel torque based on a difference between the sensed handwheel torque and the bias compensation, and control the steering actuator motor based on the grip compensated handwheel torque.

9. The steering system of claim 8, wherein the control module is operable to determine a gain compensation to adjust a scaling of the grip compensated handwheel torque between a one-handed grip and a two-handed grip handwheel steering mode.

10. The steering system of claim 9, wherein the control module is operable to determine that the one-handed grip handwheel steering mode is active based on a magnitude of the left grip or the right grip falling below a grip magnitude threshold.

11. The steering system of claim 10, wherein the gain compensation is a function of a lower value of the magnitude of the left grip and the right grip, and the gain compensation is filtered to smooth transitions in the scaling of the grip compensated handwheel torque.

12. The steering system of claim 8, wherein the net handwheel torque moment is determined based on a left grip angular position and a right grip angular position of the handwheel in reference to a straight ahead position.

13. The steering system of claim 12, wherein the net handwheel torque moment is further determined based on a left moment and a right moment in response to a nominal measure of arm weight and geometry of the left grip angular position, the right grip angular position, and the handwheel.

14. The steering system of claim 13, wherein the left moment is a product of a magnitude of the left grip and an offset based on the left grip angular position, and the right moment is a product of a magnitude of the right grip and an offset based on the right grip angular position.

15. A method for grip-based handwheel compensation, the method comprising:

determining, by a control module of a steering system, a net handwheel torque moment between a left grip and a right grip on a handwheel;

applying a filter to smooth transitions in the net handwheel torque moment as a bias compensation; and

determining a grip compensated handwheel torque based on a difference between a sensed handwheel torque and the bias compensation.

16. The method of claim 15, further comprising:

applying a one-handed scaling to the grip compensated handwheel torque to adjust scaling of the grip compensated handwheel torque between a one-handed grip and a two-handed grip handwheel steering mode as a grip and one-handed compensated handwheel torque, wherein the one-handed scaling is a gain compensation that is filtered to smooth transitions in the scaling of the grip compensated handwheel torque.

17. The method of claim 16, further comprising:

determining that the one-handed grip handwheel steering mode is active based on a magnitude of the left grip or the right grip falling below a grip magnitude threshold.

18. The method of claim 15, wherein the net handwheel torque moment is determined based on a left grip angular position and a right grip angular position of the handwheel in reference to a straight ahead position.

19. The method of claim 15, wherein the net handwheel torque moment is further determined based on a left moment and a right moment in response to a nominal measure of arm weight and geometry of the left grip angular position, the right grip angular position, and the handwheel.

20. The method of claim 19, wherein the left moment is a product of a magnitude of the left grip and an offset based on the left grip angular position, and the right moment is a product of a magnitude of the right grip and an offset based on the right grip angular position.