Methods, systems and apparatus for steering wheel vibration reduction in electric power steering systems

Patent metadata

Field	Value
Publication number	US-9440674-B2
Application number	US-88285210-A
Country	US
Kind code	B2
Filing date	Sep 15, 2010
Priority date	Sep 15, 2010
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

Methods, system and apparatus are provided for reducing steering wheel vibrations (SWVs). At least one heterodyning operation is performed during the generation of a gain-and-phase-compensated motor drive command signal. The gain-and-phase-compensated motor drive command signal is generated at a particular angular frequency, based on an angular velocity and an angular position of a wheel. The gain-and-phase-compensated motor drive command signal is communicated to an electric power steering system to control motor torque to reduce periodic content in a periodic electrical torque signal at the particular angular frequency.

First claim

What is claimed is:

1. In a vehicle comprising an electrical power steering (EPS) system, the EPS system comprising an electric motor, a method for reducing steering wheel vibrations (SWVs), the method comprising:
receiving angular position information regarding change in angular position of at least one wheel over a time interval, and generating, based on the angular position information, an instantaneous angular velocity signal and an angular position signal that corresponds to the wheel, wherein the instantaneous angular velocity signal corresponds to a particular angular frequency of the wheel;
generating a gain-and-phase-compensated motor drive command signal at the particular angular frequency, based on the instantaneous angular velocity and the angular position of the wheel, wherein generating the gain-and-phase-compensated motor drive command signal comprises the steps of:
generating, based on the angular position signal, sinusoidal carrier signals at a frequency that corresponds to the instantaneous angular velocity, wherein the sinusoidal carrier signals comprise at least two sinusoids with differences in phase;
individually mixing the sinusoidal carrier signals with an electrical torque signal to generate mixed signals;
applying one or more gains to the mixed signals to generate processed signals;
summing the processed signals to generate extracted signals; and
mixing the extracted signals with the sinusoidal carrier signals; and

communicating the gain-and-phase-compensated motor drive command signal to the electric motor to control the motor torque to attenuate vibrations communicated to a steering wheel.

2. A method according to claim 1 , wherein the step of generating the gain-and-phase-compensated motor drive command signal at the particular angular frequency further comprises:
applying gain and phase compensation to sinusoidal carrier signals to generate the gain-and-phase-compensated motor drive command signal at the particular angular frequency.

3. A method according to claim 2 , wherein a sensor is disposed between a first portion that comprises the steering wheel and that is located above the sensor, and a second portion that comprises the electric motor and that is located below the sensor, and wherein the gain-and-phase-compensated motor drive command signal causes the electric motor to adjust the motor torque to dynamically reduce periodic content in the electrical torque signal at the particular angular frequency thereby attenuating vibrations communicated to the steering wheel.

4. A method according to claim 2 , wherein a sensor is disposed between a first portion that comprises the steering wheel and that is located above the sensor, and a second portion that comprises the electric motor and that is located below the sensor, and wherein gain and phase compensation applied is determined based on an estimated transfer function which characterizes the dynamic relationship between the motor drive and the periodic electrical torque signal output by the sensor as a function of the instantaneous angular velocity.

5. A method according to claim 4 , wherein the step of generating the gain-and-phase-compensated motor drive command signal further comprises the step of:
storing a look-up table comprising a plurality of entries, wherein each entry comprises: (1) a value of instantaneous angular velocity; (2) a carrier phase angle adjustment value corresponding to the value of the instantaneous angular velocity with lead compensation, and (3) a gain adjustment value corresponding to the value of the instantaneous angular velocity.

6. A method according to claim 5 , wherein an inverse transfer function is a discretized representation of the inverse of the estimated transfer function with lead compensation, wherein the carrier phase angle adjustment value is the sum of the angle of the inverse transfer function and lead compensation at the instantaneous angular velocity, and wherein the gain adjustment value is the magnitude of the inverse transfer function at the instantaneous angular velocity.

7. A method according to claim 5 , wherein mixing the extracted signals with the sinusoidal carrier signals further comprises the steps of:
adjusting phases of the sinusoidal carrier signals based on the carrier phase angle adjustment value and lead compensation information to generate first and second phase-adjusted carrier signals;
modulating the first and second phase-adjusted carrier signals with the extracted sine signal and the extracted cosine signal, respectively, to generate first and second phase-adjusted-amplitude-modulated carrier signals;
combining the first and second phase-adjusted-amplitude-modulated carrier signals to generate a summed phase-adjusted-amplitude-modulated carrier signal; and
applying a gain based on the gain adjustment value to the summed phase-adjusted-amplitude-modulated carrier signal to generate the gain-and-phase-compensated motor drive command signal, wherein the gain is based on the gain adjustment value that corresponds to the value of the instantaneous angular velocity.

8. A method according to claim 7 , wherein the step of adjusting phases of the sinusoidal carrier signals comprises:
modifying the sine-function carrier signal based on the carrier phase angle adjustment value and the lead compensation information at the value of the instantaneous angular velocity to generate a phase-adjusted sine-function carrier signal; and
modifying the cosine-function carrier signal based on the carrier phase angle adjustment value and the lead compensation information at the value of the instantaneous angular velocity to generate a phase-adjusted cosine-function carrier signal;
wherein the step of modulating the first and second phase-adjusted carrier signals, comprises:
amplitude modulating the phase-adjusted sine-function carrier signal based on the extracted sine signal and the extracted cosine signal to generate a phase-adjusted-amplitude-modulated sine carrier signal; and
amplitude modulating the phase-adjusted cosine-function carrier signal based on the extracted sine signal and the extracted cosine signal to generate a phase-adjusted-amplitude-modulated cosine carrier signal.

9. A method according to claim 1 , wherein the step of individually mixing the sinusoidal carrier signals with an electrical torque signal to generate mixed signals comprises:
individually mixing the sinusoidal carrier signals with an electrical torque signal to generate a mixed sine signal and a mixed cosine signal, wherein the sinusoidal carrier signals comprise: a sine-function carrier signal and a cosine-function carrier signal that is 90 degrees out of phase with respect to the sine-function carrier signal;
wherein the step of applying one or more gains to the mixed signals to generate processed signals comprises:
applying one or more gains to the mixed sine signal and the mixed cosine signal to generate processed signals; and
wherein the step of summing the processed signals to generate extracted signals comprises:
summing the processed signals to generate a first extracted signal and a second extracted signal; and
wherein the step of mixing the extracted signals with the sinusoidal carrier signals comprises:
individually mixing the first extracted signal with the sine-function carrier signal and the second extracted signal with the cosine-function carrier signal.

10. A method according to claim 9 , wherein the step of individually mixing the sinusoidal carrier signals, comprises:
mixing the sine-function carrier signal and the electrical torque signal to generate a mixed sine signal that represents a quadrature component of a periodic signal observed at a torque sensor module;

Assignees

• Oblizajek Kenneth L
• Sopoci John D
• Gm Global Tech Operations Llc

Inventors

• Oblizajek Kenneth L
• Sopoci John D

Classifications

• B62D5/0472 Primary

  for damping vibrations · CPC title