Torque sensor backup in a steer-by-wire system

• US 6,609,052 B2
• Filed: 03/16/2001
• Issued: 08/19/2003
• Est. Priority Date: 03/16/2001
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Zheng, Bing, Radamis, Maged
• Primary Examiner(s): Nguyen, Tan Q.
• Assistant Examiner(s): Tran, Dalena
• Application Number:
  US09/810,277
• Publication Number:
  US 20020161499A1
• Time in Patent Office: 886 Days
• Field of Search: 701/41, 701/42, 701/43, 180/402, 180/422, 180/446, 180/405, 180/415, 180/443, 180/249
• US Class Current: 701/41
• CPC Class Codes: B62D 5/003 Backup systems, e.g. for manual steering B62D5/30 takes precedence

Abstract

A steer-by-wire system for use in a vehicle includes a driver interface system. The driver interface system includes a steering mechanism for use by an operator of the vehicle. The steer-by-wire system may allow the operator to steer the vehicle during failures within the driver interface system. When a failure is detected, the movement of the steering mechanism is controlled and torque applied by the operator to the steering mechanism is measured. The vehicle is maneuvered by the steer-by-wire system as a function of the torque applied.

Claims

1. A method of operating a steer-by-wire system in a vehicle, the method comprising:

a) detecting failure within a driver interface system;

b) sensing a torque applied by a driver of the vehicle to a steering mechanism after detection of the failure; and

c) maneuvering the vehicle as a function of the torque sensed after the failure.

2. The method of claim 1, wherein b) comprises translating the torque to movement of the steering mechanism.

3. The method of claim 1, further comprising d) controlling movement of the steering mechanism.

4. The method of claim 3, wherein d) comprises controlling operation of a friction device.

5. The method of claim 1, wherein c) comprises:

setting a value for the position of the steering mechanism;

adjusting the value as a function of the torque; and

maneuvering as a function of the adjusted value.

6. The method of claim 1, wherein a) comprises detecting a locked steering mechanism condition.

7. The method of claim 1, wherein a) comprises detecting that movement of the steering mechanism is impaired.

8. The method of claim 1, wherein a) comprises detecting the malfunction of a steering mechanism position sensor.

9. A method of maneuvering a vehicle using a steer-by-wire system when a steering mechanism within the steer-by-wire system is non-responsive to driver commands, the method comprising:

a) restricting movement of the steering mechanism;

b) sensing torque applied to the steering mechanism that is indicative of driver commands; and

c) controlling the trajectory of the vehicle as a function of the torque.

10. The method of claim 9, wherein c) comprises:

setting an initial angular position of the steering mechanism;

calculating an estimated angular position as a function of the torque; and

adjusting the trajectory as a function of the estimated angular position.

11. The method of claim 9, wherein b) comprises converting a magnitude of rotational torque to an angular position of the steering mechanism.

12. The method of claim 9, wherein a) comprises generating counter-torque with a friction device.

13. The method of claim 9, further comprising the act of initiating a torque steer mode.

14. The method of claim 9, wherein b) comprises sampling an output from a torque sensor during a time period.

15. The method of claim 9, wherein c) further comprises adjusting the turning angle of a road wheel.

16. A method of maneuverjng a vehicle using a steer-by-wire system, the method comprising;

a) detecting a failure within a driver interface system of the steer-by-wire system;

b) initiating a torque steer mode in response to the failure;

c) enabling a counter-torque to restrict movement of a steering mechanism;

d) measuring a torque applied to the steering mechanism by a driver of the vehicle;

e) calculating an estimated position of the steering mechanism as a function of the torque; and

f) adjusting an angular position of a road wheel as a function of the estimated position.

17. The method of claim 16, wherein d), e) and f) are repeated until the torque steer mode ends.

18. The method of claim 16, wherein b) comprises obtaining a position of the steering mechanism.

19. The method of claim 16, wherein a) comprises analyzing operating conditions to determine that one of a plurality of failures is occurring.

20. A steer-by-wire system for steering a vehicle, the steer-by-wire system comprising:

a driver interface system comprising a steering mechanism and a torque sensor coupled to the steering mechanism; and

a controller electrically connected with the driver interface system, the controller operable to detect failure conditions within the driver interface system,

the controller operable to steer the vehicle during failure conditions as a function of torque measurable by the torque sensor.

21. The steer-by-wire system of claim 20, wherein the driver interface system further comprises a steering mechanism position sensor and a friction device coupled to the steering mechanism.

22. The steer-by-wire system of claim 21, wherein the friction device is electrically connected with the controller and is operable to control movement of the steering mechanism as directed by the controller.

23. The steer-by-wire system of claim 20, further comprising a steering actuation system electrically connected with the controller.

24. The steer-by-wire system of claim 23, further comprising a road wheel coupled with the steering actuation system, wherein a turning angle of the road wheel is adjustable by the steering actuation system.

25. The steer-by-wire system of claim 24, wherein the turning angle is adjustable as a function of the torque.

26. The steer-by-wire system of claim 20, wherein the torque sensor is operable to measure torque applied to the steering mechanism by an operator of the vehicle.

27. The steer-by-wire system of claim 20, wherein the failure conditions are detectable as a function of operating conditions.

28. The steer-by-wire system of claim 27, wherein the operating conditions are indicative of faulty operation of the steering mechanism.

29. The steer-by-wire system of claim 28, wherein the operating conditions are indicative of operational failure of a steering mechanism position sensor.