Torque Sensor Fault Detection on Inclined Roads
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Solution Overview
Problem
Existing torque sensor fault detection methods in electric power steering systems fail to accurately identify faults when the sensor is not at its midpoint, leading to potential unbalanced steering forces and automatic steering issues.
Innovation Solution
A method that utilizes a yaw rate detection device and vehicle speed to determine if the vehicle is going straight, setting torque detection ranges for left and right offsets, and comparing steering torque direction with rudder angle to accurately identify torque sensor faults, activating backup control if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque sensor is used to detect steering torque, then the steering force can be detected and assist torque can be generated, but the torque sensor may be mistakenly detected as faulty when the vehicle is not going straight due to offset from midpoint
Solution Approach 1:
The patent changes the detection parameters by introducing yaw rate and vehicle speed as additional criteria for fault detection. By monitoring these parameters together with steering torque, the system can distinguish between actual torque sensor faults and normal operational variations when the vehicle is not going straight, thereby reducing false fault detections while maintaining reliable fault detection capability
Solution Approach 2:
The patent introduces an intermediary judgment mechanism that uses yaw rate and vehicle speed as mediating parameters. These intermediaries help bridge the gap between raw torque sensor data and accurate fault determination, allowing the system to account for vehicle dynamics and operating conditions before concluding a fault exists
2Reliability
If the magnet is peeled off in the torque sensor, then there will be an offset of about 3 to 4 Nm maintaining unbalanced steering force, but the torque sensor receives an electrical normal signal so the fault cannot be detected
Solution Approach 1:
The patent implements feedback by continuously monitoring steering torque in relation to yaw rate and vehicle speed. When a magnet peeling fault occurs, the feedback mechanism detects the abnormal torque pattern (offset of 3-4 Nm) even though the electrical signal appears normal, allowing the system to identify mechanical faults that would otherwise go undetected
Solution Approach 2:
The patent adds another dimension to fault detection by incorporating yaw rate and vehicle speed measurements alongside steering torque. This multi-dimensional approach allows the system to detect mechanical faults like magnet peeling that manifest as torque offsets, transforming a one-dimensional electrical signal check into a comprehensive multi-parameter diagnostic system
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
Prevents unbalanced steering forces and automatic steering by accurately detecting torque sensor faults, ensuring safe and stable vehicle operation.
Implementation Method 1
the displacement of the magnet is electrically detected through a detection coil
Data Source
AI summary
A torque sensor fault detection method is provided. When a torque sensor is normal when a vehicle is going straight, the torque sensor points to a torque midpoint, but when the vehicle is going straight on an inclined road, the torque midpoint is offset due to the slope of the road surface, and the torque sensor is mistakenly detected to be faulty. If a direction of a rudder angle is opposite to an offset direction of a detection value of the torque sensor, it may be judged that the torque sensor is faulty. If the two are in the same direction, the vehicle is travelling on the inclined road, and it may be judged that the torque sensor is normal, without being mistakenly detected to be faulty.