Stray magnetic field cancellation for steering torque sensor

Patent metadata

Field	Value
Publication number	US-11500040-B2
Application number	US-202016906166-A
Country	US
Kind code	B2
Filing date	Jun 19, 2020
Priority date	Jun 20, 2019
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A method for steering torque sensor stray magnetic field cancellation includes receiving, from at least one magnetic sensor disposed within a torque sensing region, a detected magnetic field corresponding to an angular displacement between an upper steering shaft and a lower steering shaft of an electronic power steering system. The method also includes generating a first torque signal based on the detected magnetic field and receiving, from at least one stray region sensor disposed outside of the torque sensing region, a detected stray magnetic field. The method also includes determining a torque signal error based on the detected stray magnetic field and generating a second torque signal based on the first torque signal and the torque signal error. The method also includes selectively controlling at least a portion of the electronic power steering system using the second torque signal.

First claim

Having thus described the present disclosure, it is claimed:

1. A system for steering torque sensor stray magnetic field cancellation, the system comprising:
a processor; and
a memory including instructions that, when executed by the processor, cause the processor to:
receive, from at least one magnetic sensor disposed within a torque sensing region, a detected magnetic field corresponding to an angular displacement between an upper steering shaft and a lower steering shaft of an electronic power steering system;
generate a first torque signal based on the detected magnetic field;
receive, from at least one stray region sensor disposed outside of the torque sensing region, a detected stray magnetic field;
determine a torque signal error based on the detected stray magnetic field;
generate a second torque signal based on the first torque signal and the torque signal error; and
selectively control at least a portion of the electronic power steering system using the second torque signal.

2. The system of claim 1 , wherein the at least one stray region sensor includes a probe.

3. The system of claim 2 , wherein the probe provides digital output.

4. The system of claim 2 , wherein the probe provides analog output.

5. The system of claim 1 , wherein the at least one magnetic sensor and the at least one stray region sensor are disposed on a printed circuit board.

6. The system of claim 1 , wherein the at least one stray region sensor shares a common power supply with the at least one magnetic sensor.

7. The system of claim 1 , wherein the at least one stray region sensor receives power from an isolated power supply that is different from a power supply that provides power to the at least one magnetic sensor.

8. The system of claim 1 , wherein the first torque signal represents an amount of torque applied to a handwheel associated with the electronic power steering system.

9. The system of claim 1 , wherein the detected magnetic field is influenced by the detected stray magnetic field.

10. The system of claim 1 , wherein the instructions further cause the processor to determine the torque signal error using a torque error model configured to estimate the torque signal error using the detected stray magnetic field.

11. A method for steering torque sensor stray magnetic field cancellation, the method comprising:
receiving, from at least one magnetic sensor disposed within a torque sensing region, a detected magnetic field corresponding to an angular displacement between an upper steering shaft and a lower steering shaft of an electronic power steering system;
generating a first torque signal based on the detected magnetic field;
receiving, from at least one stray region sensor disposed outside of the torque sensing region, a detected stray magnetic field;
determining a torque signal error based on the detected stray magnetic field;
generating a second torque signal based on the first torque signal and the torque signal error; and
selectively controlling at least a portion of the electronic power steering system using the second torque signal.

12. The method of claim 11 , wherein the at least one stray region sensor includes a probe.

13. The method of claim 12 , wherein the probe provides digital output.

14. The method of claim 12 , wherein the probe provides analog output.

15. The method of claim 11 , wherein the at least one magnetic sensor and the at least one stray region sensor are disposed on a printed circuit board.

16. The method of claim 11 , wherein the first torque signal represents an amount of torque applied to a handwheel associated with the electronic power steering system.

17. The method of claim 11 , wherein the detected magnetic field is influenced by the detected stray magnetic field.

18. The method of claim 11 , further comprising determining the torque signal error using a torque error model configured to estimate the torque signal error using the detected stray magnetic field.

19. An apparatus comprising:
at least one magnetic sensor that detects a magnetic field within a torque sensing region, the detected magnetic field corresponding an amount of torque applied to a handwheel associated with an electronic power steering system;
at least one stray region sensor that detects a stray magnetic field outside of the torque sensing region, the detected magnetic field being influenced by the detected stray magnetic field; and
a controller configured to:
generate a first torque signal based on the detected magnetic field;
determine a torque signal error based on the detected stray magnetic field;
generate a second torque signal based on the first torque signal and the torque signal error; and
selectively control at least a portion of the electronic power steering system using the second torque signal.

20. The apparatus of claim 19 , wherein the controller is further configured to determine the torque signal error using a torque error model configured to estimate the torque signal error using the detected stray magnetic field.

Assignees

• Steering Solutions Ip Holding

Inventors

• Moore Jared K
• Cammin Clane J
• Kidder Keith A

Classifications

• G01R33/0029

  Treating the measured signals, e.g. removing offset or noise · CPC title

• B62D5/04 Primary

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title

• B62D6/00

  Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title

• B62D15/02

  Steering position indicators {; Steering position determination; Steering aids} · CPC title