Torque Disturbance Rejection in Power Steering Systems
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Solution Overview
Problem
Power steering systems in vehicles experience undesirable tactile vibrations (torque disturbances) due to the position of components like motors, gears, and linkages, which affect the driver's steering experience.
Innovation Solution
A method and system that utilize a controller to receive position and disturbance signals, calculate counteracting torque signals, and send these signals to the motor to minimize torque disturbances by combining them with assist torque commands, using sinusoidal waves to cancel out harmonic disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If position feedback from steering system components is used to generate torque commands, then steering assist functionality is provided, but torque disturbances and tactile vibrations are introduced at the handwheel
Solution Approach 1:
The controller calculates a counteracting torque command signal based on the detected component position and disturbance characteristics, then applies this counteracting torque in advance to offset the harmful torque disturbances before they reach the handwheel, thereby eliminating vibrations while preserving steering assist functionality
Solution Approach 2:
The system converts the harmful torque disturbances generated by steering components into useful information by detecting the disturbance signals and using them to generate compensating torque commands, thereby transforming the harmful vibrations into a benefit where the disturbance information itself becomes the basis for eliminating the disturbance
2Object-affected harmful factors
If disturbance cancellation signals are added to minimize torque disturbances, then handwheel vibrations are reduced, but control system complexity increases
Solution Approach 1:
The controller merges the disturbance cancellation functionality with the existing steering assist control by integrating the counteracting torque calculation into the same control unit that generates assist torque commands, using a single processor to handle both functions without requiring separate dedicated hardware systems
Solution Approach 2:
The system implements feedback by continuously monitoring the actual torque disturbances at the handwheel through position sensors and using this feedback information to dynamically adjust the counteracting torque commands, creating a closed-loop control system that automatically adapts to varying disturbance conditions
Data Source
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AI summary
A method for controlling a steering system, the method including, receiving a first signal including a position of a component in the steering system, receiving a second signal including a disturbance signal operative to indicate an effect of a first torque disturbance in the steering system, calculating a first counter acting torque command signal operative to minimize the first torque disturbance as a function of the position of the component and the disturbance signal, and sending the first counter acting torque command signal to a motor.