Steer-by-Wire Coupling Wear Detection Through Frequency Analysis
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Solution Overview
Problem
Steer-by-wire systems face challenges due to mechanical wear and tear in the coupling between the servomotor and steering wheel, affecting haptic feedback and positioning accuracy, which are not effectively addressed by existing methods.
Innovation Solution
A method and system that analyze the temporal behavior of the steering wheel position using frequency spectrum analysis to detect mechanical coupling wear, allowing for early detection and compensation of mechanical degradation by adjusting control parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mechanical coupling is used between the servomotor and steering wheel, then torque transmission is achieved, but mechanical wear and tear occurs over time affecting positioning accuracy and haptic feedback
Solution Approach 1:
The system performs preliminary diagnostic actions by continuously monitoring the mechanical coupling's condition through vibration analysis and temporal behavior detection. This early detection allows for compensatory measures to be taken before wear significantly degrades positioning accuracy, thus maintaining reliability while using mechanical coupling for torque transmission.
Solution Approach 2:
The control unit continuously monitors the temporal behavior of the mechanical coupling and uses this feedback to detect wear and tear. Based on this feedback, the system can adapt control parameters to compensate for degradation, maintaining positioning accuracy despite the mechanical wear inherent in using a mechanical coupling for torque transmission.
2Force
If mechanical coupling components are used, then torque can be transmitted, but friction behavior changes over time due to wear
Solution Approach 1:
The system utilizes mechanical vibration analysis to detect changes in friction behavior. By analyzing the vibration characteristics and temporal profiles of the mechanical coupling, the control unit can identify wear-induced friction changes that would otherwise be difficult to detect, enabling early intervention while maintaining effective torque transmission.
Solution Approach 2:
The system replaces direct mechanical measurement of friction with an electronic/digital monitoring approach. Instead of mechanically measuring friction directly, the control unit uses sensors and signal processing to detect friction behavior changes through vibration analysis and temporal behavior monitoring, making detection easier while torque is still transmitted mechanically.
3Reliability
If wear detection mechanisms are added, then mechanical coupling state can be monitored, but system complexity increases
Solution Approach 1:
The control unit is designed to perform multiple functions: it controls the servomotor for positioning, generates haptic feedback, and simultaneously monitors the mechanical coupling's condition. By making the control unit multi-functional, the system achieves reliable wear detection without adding separate dedicated monitoring hardware, thus avoiding excessive complexity while maintaining detection capability.
Solution Approach 2:
The diagnostic and monitoring functions are merged with the existing control functions in the control unit. Instead of adding separate wear detection mechanisms, the system combines condition monitoring with the servomotor control and haptic feedback generation, achieving reliable wear detection while minimizing system complexity through functional integration.
Data Source
Figure 1~4
AI summary
The invention relates to a method for checking a steer-by-wire steering system (1), the steering system (1) comprising a steering device (2) connected to vehicle wheels, a steering wheel (3), an actuator (4), and a control unit (5), the actuator (4) being configured to exert a torque (10) on the steering wheel (3) via a mechanical coupling (7), and the control unit (5) being configured to correlate a steering wheel angle (6) of the steering wheel (3) with a steering angle of the steering device (2) by controlling the actuator (4) in a closed-loop manner, the method comprising the following steps: in a closed-loop control step, the actuator (4) of the steering wheel (3) is controlled in a closed-loop manner in such a way that the steering wheel angle (6) is correlated with a desired angle (9), a temporal progression (8) of a state variable (20) of the steering wheel (3) and/or of the actuator (4) being determined; in an analysis step, a frequency spectrum (18) of the temporal progression (8) of the state variable (20) is determined and an amplitude of a predefined spectral component of the frequency spectrum (18) is determined; in a classification step, a state of the mechanical coupling (7) is classified depending on the amplitude of the spectral component. The invention also relates to a steer-by-wire steering system (1) and to a vehicle comprising such a steering system.