Sensor Device Torque Computation Abnormality Detection
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Solution Overview
Problem
Existing electric power steering systems with dual torque sensors face challenges in maintaining accurate abnormality detection and torque computation when one or more sensor elements fail, leading to reduced accuracy and potential system failures.
Innovation Solution
A sensor device with multiple sensor units and control units that enable signal comparison and torque computation even when some sensor elements are abnormal, by transmitting and receiving detection signals between control units to identify and compensate for faulty sensors, ensuring continuous abnormality monitoring and torque computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abnormality detection is performed by comparing detection values of both torque sensors, then abnormality detection capability is maintained, but abnormality detection accuracy is lowered when one sensor is abnormal
Solution Approach 1:
The patent creates a backup copy of detection signals by having control units exchange and store detection signals from both sensor units. When one sensor unit is abnormal, the control unit can use the copied detection signals from the other sensor unit to maintain accurate abnormality detection, avoiding the accuracy degradation that would occur if only direct comparison was used.
Solution Approach 2:
The patent prepares for potential sensor failures by having control units continuously exchange and store detection signals from both sensor units before any abnormality occurs. This beforehand cushioning ensures that when a sensor failure is detected, the system already has backup data available to maintain accurate abnormality detection without interruption.
2Productivity
If steering assist control continues with one torque sensor after abnormality detection, then steering assistance is maintained, but system reliability is reduced due to potential computation errors
Solution Approach 1:
The patent implements feedback mechanisms where control units continuously monitor the status of both torque sensor units and exchange detection signals. When an abnormality is detected in one sensor unit, the system uses feedback information to switch to using only the normal sensor unit for torque computation, preventing computation errors while maintaining steering assistance continuity.
Solution Approach 2:
The patent creates redundant copies of detection signals by having control units store detection signals from both sensor units. When one sensor is abnormal, the system can switch to using the copied detection signals from the other sensor unit, ensuring continuous steering assistance while maintaining reliability through the backup copy.
3Reliability
If dual torque sensor system is used, then abnormality detection capability is provided, but device complexity is increased
Solution Approach 1:
The patent makes the control units multi-functional by enabling them to perform both normal torque computation and abnormality detection using detection signals from either sensor unit. The control units can switch between processing modes based on sensor status, reducing the need for separate dedicated abnormality detection hardware and thereby reducing overall system complexity while maintaining reliability.
Data Source
AI summary
A sensor device includes: multiple sensor units, each of which includes multiple sensor elements and a signal processing unit that generates and transmits an output signal including multiple detection signals corresponding to detection values of the sensor elements; and multiple control units, each of which includes a communication unit that receives the output signal, an abnormality monitoring unit that monitors abnormality of the respective sensor unit, and a physical quantity computation unit that computes a physical quantity based on at least one of the detection signals which is normal. One control unit mutually transmits and receives the detection signals as subject sensor signals received from the respective sensor unit and the detection signals as other sensor signals received from another one of the control units with another system control unit.