Motor-Driven Power Steering Reverse Gain Control
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Solution Overview
Problem
Conventional motor-driven power steering (MDPS) systems fail to effectively mitigate steering unfamiliarity such as sticky or stuck feel during reverse steering operations, despite attempts to improve steering feel by controlling column torque.
Innovation Solution
An apparatus and method that utilize sensors to detect steering angle, angular speed, and column torque, with a controller determining reverse steering operations and applying optimized compensation gains to enhance responsiveness, including phase compensation, gain selection, and high-frequency filtering to stabilize the compensation gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional column torque compensation is applied during reverse steering, then steering feel is improved, but responsiveness remains insufficient causing sticky or stuck feel
Solution Approach 1:
The controller pre-stores multiple compensation gain values (first gain for reverse steering, second gain for non-reverse steering) in advance. When reverse steering is detected through phase compensation and code transition, the controller immediately switches to the pre-prepared first gain value, eliminating calculation delays and achieving instantaneous responsiveness improvement.
Solution Approach 2:
The system dynamically adjusts the compensation gain based on steering direction. By detecting phase transitions in the steering angle signal and determining whether reverse steering occurs, the controller switches between different compensation gain values (first gain for reverse, second gain for non-reverse), making the system adaptive to different operating conditions and resolving the contradiction between steady-state feel and transient responsiveness.
2Speed
If compensation gain is increased to improve responsiveness, then steering responsiveness improves, but system stability may be compromised
Solution Approach 1:
Different compensation gain values are applied to different steering conditions. The first gain (higher value) is specifically applied only during reverse steering operations to improve responsiveness when needed, while the second gain (lower value) is used during normal non-reverse steering to maintain system stability. This localized application of different gain values resolves the contradiction between responsiveness and stability.
Solution Approach 2:
The system changes the compensation gain parameter based on steering direction detection. By monitoring phase transitions in the steering angle signal and switching between different gain values (first gain for reverse, second gain for non-reverse), the system optimizes responsiveness during critical reverse steering while maintaining stability during normal operation through parameter adaptation.
Data Source
AI summary
Disclosed herein are an apparatus and method of controlling a motor-driven power steering system. The apparatus may include: a sensor configured to detect at least one of a steering angle, an angular speed, and a column torque in the motor-driven power steering system; and a controller configured to determine whether a reverse steering operation has been performed based on the steering angle or the angular speed, and configured to output, when non-reverse steering, a high-frequency compensation gain (a second gain) based on the column torque, as a final compensation gain, and output, when reverse steering, a value obtained by applying an additional compensation gain (a first gain) optimized corresponding to an angular acceleration to the high-frequency compensation gain (the second gain), as the final compensation gain.