Electric Power Steering Control Unit Vibration Suppression
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Solution Overview
Problem
Conventional electric power steering systems face challenges in efficiently suppressing vibrations in the steering wheel and motor speed, leading to increased processing capacity and inadequate vibration control across all frequency ranges, with existing solutions failing to effectively manage vibrations and improve steering feel.
Innovation Solution
An electric power steering control unit that employs a band pass filter to extract specific frequency components of vibrations, uses Fourier series calculations to determine vibration continuation, and adjusts PI control gains only when vibrations persist within a predetermined frequency and time, thereby reducing calculation complexity and enhancing vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional vibration suppression methods are used to suppress steering wheel vibrations, then vibration suppression is achieved, but calculation capacity increases and processing becomes less efficient
Solution Approach 1:
The patent segments the vibration suppression task by dividing the frequency spectrum into specific frequency ranges and applying different suppression strategies to each range. The vibration suppression is segmented into: (1) frequency range determination based on steering angle and angular velocity, (2) phase difference calculation between steering torque and steering angle, and (3) selective suppression based on phase difference thresholds. This segmentation allows efficient processing by focusing computational resources only on relevant frequency ranges rather than analyzing the entire spectrum.
Solution Approach 2:
The patent implements dynamic adjustment of vibration suppression parameters based on real-time steering conditions. The frequency range and phase difference thresholds are dynamically determined based on steering angle and angular velocity, allowing the system to adapt to changing operating conditions. This dynamic approach enables the system to maintain high processing efficiency while effectively suppressing vibrations across varying steering scenarios.
2Object-affected harmful factors
If vibration suppression is applied across all frequency ranges, then comprehensive vibration control is achieved, but calculation complexity increases
Solution Approach 1:
The patent applies local quality by tailoring the vibration suppression characteristics to specific frequency ranges and steering conditions. Different phase difference thresholds and suppression gains are applied to different frequency ranges based on the steering angle and angular velocity. This localized approach ensures that computational complexity is minimized by applying complex calculations only where necessary, rather than uniformly across all frequencies.
Solution Approach 2:
The patent implements partial action by selectively applying vibration suppression only to specific frequency ranges that are identified as problematic based on steering conditions. Rather than applying suppression across the entire frequency spectrum, the system identifies relevant frequency ranges and applies targeted suppression, reducing overall calculation complexity while maintaining effective vibration control.
3Object-affected harmful factors
If existing vibration suppression methods are used, then some vibration control is achieved, but steering feel is not adequately improved
Solution Approach 1:
The patent implements feedback by continuously monitoring steering torque, steering angle, and angular velocity to dynamically adjust vibration suppression parameters. The phase difference between steering torque and steering angle is calculated and used to determine the appropriate suppression gain and frequency range. This feedback mechanism ensures that vibration suppression is optimized in real-time, improving steering feel by adapting to the driver's steering actions and road conditions.
Solution Approach 2:
The patent changes key parameters (frequency range, phase difference thresholds, suppression gain) based on steering angle and angular velocity to optimize steering feel. By dynamically adjusting these parameters according to operating conditions, the system achieves better vibration suppression that enhances steering feel without creating artificial resistance or disrupting the natural steering feedback.
Data Source
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AI summary
[Problem] An object of the present invention is to provide an electric power steering control unit that detects the vibration components of the vibration compressing object such as the handle and current command value based on an expression of Fourier series of which calculation capacity is small, changes a gain of the PI control section at only a time when the vibration of the predetermined frequency continues during the predetermined time or more and compresses the vibration, and improves the steering feeling. [Means for solving the problem] The present invention comprises a vibration detecting section to detect a vibration of a vibration compressing object and outputs a vibration signal; a continuation-time judging section to output a continuation signal when the vibration signal continues equal to or more than a predetermined time; and a gain setting section to change a gain of the PI-control based on the continuation signal; wherein a vibration compressing of the vibration compressing object is performed in a continuation of a predetermined frequency of the vibration signal and being equal to or more than the predetermined time.