Electric Power Steering Analog State Ratio Control
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Solution Overview
Problem
Conventional electric power steering systems cause uncomfortable feelings for drivers due to chattering and sudden changes in steering state judgments, leading to torque ripples, vibrations, and abnormal noises during turning and returning maneuvers.
Innovation Solution
An electric power steering apparatus that calculates a turning or returning state index and ratio based on steering torque and motor angle velocity, using a convergence control section with gain correction and output processing to provide finer control and reduce uncomfortable feelings by making steering state judgments analog rather than digital.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital judgment of steering state (turning/returning) is used, then control simplicity is maintained, but chattering and sudden changes occur causing uncomfortable driving feelings
Solution Approach 1:
The patent changes the parameter type from digital (discrete turning/returning states) to analog (continuous ratio value between 0-1). The steering state is represented by a continuous ratio calculated from steering torque and angle velocity, allowing smooth transitions and eliminating chattering while maintaining control simplicity.
Solution Approach 2:
The patent introduces dynamic adjustment of the turning/returning state ratio based on real-time steering conditions. The ratio is continuously updated based on steering torque and angle velocity, enabling adaptive control that responds smoothly to changing steering states without sudden transitions.
2Reliability
If conventional feedback control is used, then basic steering assist is achieved, but torque ripples and abnormal noises occur during convergence control
Solution Approach 1:
The patent enhances feedback control by continuously monitoring steering torque and angle velocity to calculate the turning/returning state ratio. This refined feedback mechanism allows the system to detect subtle changes in steering state and adjust convergence control accordingly, eliminating torque ripples and abnormal noises.
Solution Approach 2:
The patent performs preliminary calculation of the turning/returning state ratio based on current steering conditions before executing convergence control. By pre-determining the appropriate control ratio, the system可以避免sudden control adjustments that cause torque ripples and abnormal noises during steering convergence.
Data Source
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AI summary
[Problem] An object of the present invention is to provide a high-performance electric power steering apparatus that reduces uncomfortable feeling of a driver by improving judgment of turning or returning and performing fine control of a steering state to improve a function of convergence control. [Means for solving the problem] An electric power steering apparatus comprises: a turning or returning state index calculating section that calculates a turning or returning state index based on a steering torque and a motor angle velocity; a turning or returning state ratio calculating section that calculates a turning or returning state ratio with a nominal value as a reference based on the turning or returning state index; and a convergence control section that comprises a sensitive gain section that calculates a turning gain and a returning gain based on the steering torque, a vehicle speed and the motor angle velocity, a gain correcting section that performs gain correction for the turning gain and the returning gain by the turning or returning state ratio, and an output processing section that outputs a convergence control value by performing output processing of a gain signal from the gain correcting section based on an absolute value and a sign inversion signal of a yaw rate estimation value.