Torque Data Robusting Device for EPS Sensor Failure
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Solution Overview
Problem
The Electric Power Steering (EPS) system faces challenges in assisting driver steering when the torque sensor fails, leading to increased driver load during reverse steering and fixed compensation torque at varying vehicle speeds, which can hinder vehicle stability.
Innovation Solution
A torque data robusting device and method that uses sensor information to generate a compensation torque based on steering angle and vehicle speed, determining whether the steering is normal or reverse to adjust the compensation torque accordingly, thereby minimizing driver effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compensation torque is generated to assist steering when torque sensor fails, then steering assist capability is improved, but reverse steering becomes difficult due to excessive compensation torque
Solution Approach 1:
The compensation torque is made dynamic by adjusting its magnitude based on steering angular velocity. When reverse steering is detected (high angular velocity), the compensation torque is reduced or canceled, allowing the driver to steer back easily. When normal steering occurs (low angular velocity), full compensation torque is applied to assist the driver.
Solution Approach 2:
The system changes the parameter of compensation torque magnitude based on steering conditions. By monitoring steering angular velocity and comparing it to a threshold, the system switches between different torque levels (full compensation, reduced compensation, or zero compensation) to optimize both steering assist and reverse steering capability.
2Reliability
If fixed compensation torque is applied at all vehicle speeds, then steering assist is provided, but vehicle stability deteriorates due to inappropriate torque at varying speeds
Solution Approach 1:
The compensation torque is made speed-dependent by continuously adjusting its magnitude based on the host vehicle's speed. At low speeds, higher compensation torque is applied to assist steering maneuvers. At high speeds, the compensation torque is reduced to maintain vehicle stability and prevent over-assist conditions.
Solution Approach 2:
The system changes the compensation torque parameter according to vehicle speed by comparing speed signals against predefined thresholds. This creates a speed-adaptive compensation torque that provides appropriate assist levels for different driving conditions, maintaining both steering assist capability and vehicle stability.
3Reliability
If compensation torque is generated without considering steering direction, then steering assist is provided, but driver load increases during return steering due to fixed torque
Solution Approach 1:
The compensation torque is made directional by detecting the sign of steering angular velocity. When return steering is detected (negative angular velocity), the compensation torque is reduced or reversed to match the driver's intended motion, reducing the force the driver must apply to return the steering wheel to center position.
Data Source
AI summary
The embodiments of the present disclosure relate to a torque data robusting device and method. Specifically, the torque data robusting device according to the present disclosure may include a sensor unit for sensing a speed of a host vehicle, a steering angle and a steering torque for a steering wheel, and a controller configured to generate, if a steering torque value is not received from the sensor unit, a compensation torque to assist an user's steering based on the steering angle and the speed of the host vehicle, determine whether the user's steering is a normal steering or a return steering according to the steering angle and a steering angular velocity, and control to generate and adjust the compensation torque according to the normal steering or the return steering.