Vehicle Control System Torque Sensor Friction Estimation
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Solution Overview
Problem
Existing vehicle control systems face inaccuracies in determining whether a driver is in a hands-on or hands-off state during automatic steering control due to variations in friction torque caused by temperature and part deterioration, leading to potential lane departure and decreased controllability.
Innovation Solution
A vehicle control system that includes a torque sensor to detect torque on the steering shaft and a control device capable of repeatedly estimating the upper friction torque and setting a variable determination threshold, ensuring accurate driver state determination by comparing sensor-detected torque with the estimated threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If friction torque is given a fixed value beforehand estimated through tests, then device complexity is reduced, but measurement precision of driver state determination deteriorates
Solution Approach 1:
The patent applies the Dynamics principle by transforming the static fixed friction torque value into a dynamic variable that is continuously updated based on actual vehicle operating conditions. The control device repeatedly estimates the upper friction torque during automatic steering control execution, allowing the friction torque parameter to adapt to changing temperature environments and part deterioration states, thereby maintaining high measurement precision without excessive complexity
Solution Approach 2:
The patent implements Feedback by using the torque sensor to continuously detect actual torque values during automatic steering control and comparing them against estimated upper friction torque values. This feedback mechanism allows the system to learn and update the friction torque characteristics in real-time, improving determination accuracy while keeping the system relatively simple through iterative estimation rather than complex predetermined models
2Ease of operation
If friction torque is given a fixed value, then ease of operation is improved, but reliability of driver state determination deteriorates
Solution Approach 1:
The patent applies Self-service by enabling the system to automatically estimate and update its own friction torque parameters during normal operation. The control device performs repeated estimation of upper friction torque using torque sensor data from actual steering operations, allowing the system to self-calibrate and maintain reliable driver state determination without requiring manual intervention or complex external calibration procedures
Solution Approach 2:
The patent implements Preliminary action by establishing an initial upper friction torque value before automatic steering control begins, then using this preliminary estimate as a baseline for subsequent real-time updates. This approach allows the system to start with a simple fixed value for ease of operation while progressively improving reliability through repeated estimation during actual use
Data Source
AI summary
A turning mechanism of a vehicle turns a wheel and is coupled to a steering wheel through a steering shaft. A torque sensor detects a torque applied to a first position of the steering shaft, as a sensor-detected torque. An upper friction torque is an absolute value of the sensor-detected torque that is caused by a friction force acting on the steering shaft between the first position and the steering wheel when the steering shaft is rotated. A vehicle control system repeatedly estimates the upper friction torque and variably sets a determination threshold to the estimated upper friction torque or more. The vehicle control system determines whether a driver state is a hands-on state or a hands-off state based on a comparison between the absolute value of the sensor-detected torque and the determination threshold.