Torque Sensor Hysteresis Compensation for Steering Systems
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Solution Overview
Problem
Vehicle steering systems with torque sensors often experience hysteresis issues, leading to errors in torque signal measurement, which result in poor steering feel and conditions like leads and pulls, particularly in lower cost designs with manufacturing and angle sensing technologies that exhibit hysteresis.
Innovation Solution
A method and system for compensating torque sensor hysteresis by determining a full hysteresis value and a shift value, calculating a product, and generating a modified torque signal to correct for hysteresis, thereby improving steering accuracy and feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lower cost manufacturing and angle sensing technologies are used in torque sensors, then device cost is reduced, but measurement precision deteriorates due to hysteresis errors
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the torque signal through hysteresis compensation. The system determines a hysteresis value based on the current state of the torque sensor and modifies the torque signal accordingly, changing the signal parameters to compensate for measurement errors caused by hysteresis in lower cost sensors
Solution Approach 2:
The patent replaces mechanical improvement (using higher precision, more expensive torque sensors) with an electronic/software-based solution. By implementing hysteresis compensation algorithms and signal modification techniques, the system substitutes mechanical precision requirements with computational correction methods
2Measurement precision
If hysteresis compensation is implemented through signal modification, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the controller perform multiple functions: it not only controls the steering actuator but also determines hysteresis values, modifies torque signals, and compensates for measurement errors. By integrating these functions into the existing controller, the patent avoids adding separate dedicated hardware components for hysteresis compensation
Solution Approach 2:
The system performs self-diagnosis and self-correction by determining its own hysteresis characteristics and automatically compensating for them. The controller monitors its own performance and adjusts the torque signal accordingly, eliminating the need for external calibration equipment or additional compensation devices
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces errors in torque signal measurement, enhancing steering feel and reducing leads and pulls conditions in vehicles by modifying the torque signal to account for hysteresis, thus improving the overall performance of steering systems.
Implementation Method 1
torque sensor hysteresis compensation... determining a full hysteresis value associated with the torque sensor... hysteresis issues, leading to errors in torque signal measurement
Data Source
AI summary
A method for compensating for torque sensor hysteresis. The method includes receiving, from a torque sensor, a first torque signal corresponding to a torque applied to a handwheel associated with a steering system; determining a full hysteresis value associated with the torque sensor; determining a shift value based on the full hysteresis value; calculating a product of the full hysteresis value and the shift value; generating a modified torque signal based on the first torque signal and the product of the full hysteresis value and the shift value; and determining a torque assist value based on the modified torque signal.