Multi-Channel Torque Sensor for Electric Power Steering Safety
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Solution Overview
Problem
Existing electric power steering apparatuses face reliability issues due to limited sensor signals, which can lead to abnormal steering control when sensor abnormalities occur, especially with the increasing complexity of electronic vehicle systems and the need for enhanced safety, particularly with the integration of autonomous driving technologies.
Innovation Solution
The implementation of a three-channel or four-channel torque sensor system, combined with a three-channel or single-wound Brushless AC motor, and an Electronic Control Unit (ECU) that selects and combines signals for reliable steering control, even in the presence of sensor abnormalities, thereby enhancing the safety integrity level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of sensor signals is increased to improve safety, then the reliability of steering control is improved, but the device complexity increases
Solution Approach 1:
The torque sensor is divided into multiple channels (three-channel or four-channel configuration) with independent signal paths. Each channel processes torque signals separately, allowing the system to identify and exclude abnormal signals while maintaining reliable steering control through the remaining healthy channels.
Solution Approach 2:
Different channels are assigned to detect different physical quantities or signal types (e.g., torque, steering angle, motor position). This local differentiation allows the ECU to selectively use appropriate signals based on their quality and reliability, improving overall system safety without requiring all sensors to be identical.
2Reliability
If multiple independent dual die ICs are used in torque sensor, then the safety integrity level is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The torque sensor employs multiple independent dual die ICs that can be manufactured separately and then assembled. This segmentation allows each IC to be produced using standardized processes, and the final assembly integrates them into a multi-channel sensor system with enhanced reliability without requiring entirely new manufacturing infrastructure.
Data Source
AI summary
The present disclosure relates to an electric power steering apparatus. An embodiment of the present disclosure provides an electric power steering apparatus including a three-channel torque sensor, a three-channel motor position sensor, and a single-wound BLAC motor, and an ECU configured to control steering.