MOTOR POSITION FILTER FOR ESTIMATION OF VELOCITY USING MOVING LINEAR REGRESSION

• US 20150025837A1
• Filed: 07/18/2014
• Published: 01/22/2015
• Est. Priority Date: 07/19/2013
• 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: Collier-Hallman, Steven J.
• Granted Patent: US 10,173,718 B2
• Time in Patent Office: Days
• US Class Current: 702/147
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/049 detecting sensor failures
• CPC Class Codes: G01P 3/64 Devices characterised by the determination of the time taken to traverse a fixed distance
• CPC Class Codes: H03M 1/1265 Non-uniform sampling

Abstract

A method of estimating a motor velocity in an electric power steering system that includes a motor is provided. The method generates motor position data by sampling an original motor position signal at an irregular sampling rate. The method estimates a motor velocity by performing a regression analysis on the motor position data.

Claims

1. A method of estimating a motor velocity in an electric power steering system that includes a motor, comprising:

generating motor position data by sampling an original motor position signal at an irregular sampling rate; and

estimating a motor velocity by performing a regression analysis on the motor position data.

2. The method of claim 1, wherein the original motor position signal is generated by sampling shaft positions of the motor at a regular sampling rate.

3. The method of claim 1, wherein the generated motor position data includes a plurality of motor position values and a plurality of corresponding time values.

4. The method of claim 3, further comprising

determining that one of the plurality of motor position values is to be unwrapped;

and

unwrapping the motor position value.

5. The method of claim 3, further comprising:

determining that one of the plurality of the time values is to be unwrapped; and

unwrapping the time value.

6. The method of claim 3, further comprising adjusting the time values by subtracting an average of the time values from each of the time values.

7. The method of claim 3, wherein the estimating a motor velocity comprises:

generating a first sum of all products of the motor position values and the corresponding time values;

generating a second sum of all of squared time values; and

generating an estimated motor velocity by dividing the first sum by the second sum.

8. A system comprising:

a power steering system that includes a motor; and

a control module configured to;

generate motor position data by sampling an original motor position signal at an irregular sampling rate; and

estimate a motor velocity by performing a regression analysis on the motor position data.

9. The system of claim 8, wherein the original motor position signal is generated by sampling shaft positions of the motor at a regular sampling rate.

10. The system of claim 8, wherein the generated motor position data includes a plurality of motor position values and a plurality of corresponding time values.

11. The system of claim 10, wherein the control module is further configured to:

determine that one of the motor position values is to be unwrapped; and

unwrap the motor position value.

12. The system of claim 10, wherein the control module is further configured to:

determine that one of the time values is to be unwrapped; and

unwrap the time value.

13. The system of claim 10, wherein the control module is further configured to adjust the time values by subtracting an average of the time values from each of the time values,

14. The system of claim 10, wherein the control module is configured to estimate a motor velocity by:

generating a first sum of all products of the motor position values and the corresponding time values;

generating a second sum of all of squared time values; and

generating an estimated motor velocity by dividing the first sum by the second sum.

15. A control system for estimating a motor velocity in an electric power steering system that includes a motor, comprising:

a sampling module configured to generate motor position data by sampling an original motor position signal at an irregular sampling rate; and

a motor velocity estimation module configured to estimate a motor velocity by performing a regression analysis on the motor position data.

16. The control system of claim 15, wherein the original motor position signal is generated by sampling shaft positions of the motor at a regular sampling rate.

17. The control system of claim 15, wherein the generated motor position data includes a plurality of motor position values and a plurality of corresponding time values.

18. The control system of claim 17, further comprising:

a position unwrap module configured to;

determine that one of the motor position values is to be unwrapped; and

unwrap the motor position value; and

a time unwrap module configured to;

determine that one of the time values is to be unwrapped; and

unwrap the time value when the time value is determined to be unwrapped.

19. The control system of claim 17, further comprising a time adjustment module configured to adjust the time values by subtracting an average of the time values from each of the time values.

20. The control system of claim 17, wherein the motor velocity estimation module is configured to estimate a motor velocity by:

generating a first sum of all products of the motor position values and the corresponding time values;

generating a second sum of all of squared time values; and

generating an estimated motor velocity by dividing the first sum by the second sum.