Adaptive Filter for Electronic Power Steering Vibration Reduction
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Solution Overview
Problem
Electronic power steering systems experience vibrations due to their complex algorithm structure and high computational load, leading to driver fatigue and suboptimal driving conditions, as existing methods like heterodyne algorithms are slow and cumbersome to tune.
Innovation Solution
An apparatus and method utilizing a vibration filter unit, signal generation unit, adaptive filter, and error unit to detect and reduce steering vibrations by generating a current control signal based on wheel speed and vibration data, with a gain unit modifying the signal's level and phase, and an adaptive finite impulse response filter updating its coefficients in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heterodyne algorithm is used to reduce vibrations, then vibration reduction effectiveness is improved, but computational complexity and tuning time increase significantly
Solution Approach 1:
The patent extracts only the necessary vibration reduction function from the complex heterodyne algorithm by implementing a dedicated vibration reduction unit that separately processes torque sensor signals. This unit specifically targets vibration frequency components and extracts only the essential correction signals, leaving out the cumbersome tuning and computation elements of the original heterodyne approach.
Solution Approach 2:
The steering control system is segmented into distinct functional units: a torque sensor for detecting steering torque, a vibration reduction unit for processing the torque signal and reducing vibrations, and a motor controller for executing the corrected signals. This segmentation allows the vibration reduction function to be optimized independently without affecting the entire system, reducing overall complexity.
2Reliability
If a heterodyne algorithm is used to reduce vibrations, then vibration reduction effectiveness is improved, but tuning time and computational load increase
Solution Approach 1:
The vibration reduction unit operates autonomously by directly processing torque sensor signals in real-time without requiring external tuning parameters or complex pre-calibration. The system self-adjusts to vibration conditions by continuously analyzing torque signals and generating appropriate correction signals, eliminating the time-consuming tuning process inherent in heterodyne algorithms.
Solution Approach 2:
The patent replaces the mechanical tuning process of traditional heterodyne algorithms with an electronic signal processing approach. The vibration reduction unit uses electronic filtering and signal manipulation to achieve vibration reduction without requiring physical adjustments or lengthy tuning procedures, thereby eliminating computational overhead and tuning time.
3Manufacturing precision
If complex vibration reduction algorithms are implemented, then vibration control precision is improved, but real-time processing capability deteriorates
Solution Approach 1:
The vibration reduction unit applies localized signal processing only to the vibration frequency components of the torque signal, rather than processing the entire signal spectrum with complex algorithms. By focusing computational resources on specific frequency bands where vibrations occur, the system achieves precise vibration control while maintaining real-time processing capability for other steering control functions.
Data Source
AI summary
An apparatus for reducing vibrations of an electronic steering apparatus includes a vibration filter unit which extracts a steering vibration signal that is a radio frequency component of a torque signal transmitted from a torque sensor, a signal generation unit which generates a reference signal based on one of a wheel speed and a wheel vibration number transmitted from a sensor mounted in a vehicle, an adaptive filter which receives the reference signal generated by the signal generation unit and generates a current control signal, a motor which receives the current control signal, and an error unit which stores a steering vibration component value generated based on the steering vibration signal and the current control signal applied to the motor. Here, the steering vibration component value stored in the error unit is provided as feedback to the adaptive filter to update the adaptive filter with a coefficient.