Rotation Angle Sensor Redundancy for Common Cause Failure
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Solution Overview
Problem
Existing motor rotation angle detection systems face challenges in accurately determining normal sensor output when both primary and secondary sensors fail simultaneously due to common cause failures, potentially leading to erroneous identification of abnormal sensor outputs as normal.
Innovation Solution
The detection unit employs a redundant sensor system with distinct detection elements and power sources, utilizing a controller to generate a reference signal from normal sensor outputs and compare it with individual sensor outputs to identify and isolate abnormal signals, ensuring continued normal output even if two detection elements fail due to a common cause.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundant rotation angle sensor is used to identify normal sensors by comparing outputs, then the system can continue operation when one sensor fails, but when multiple sensors fail simultaneously due to common cause failure, the system may incorrectly identify abnormal outputs as normal
Solution Approach 1:
The patent segments the sensor system into multiple independent detection elements (main sensor, sub sensor, and redundant sensor) that can be individually evaluated. By dividing the sensor array and comparing outputs across segments, the system can identify which specific sensors are functioning normally even when some fail, preventing common cause failures from compromising the entire measurement system.
Solution Approach 2:
The patent introduces a rotation angle calculator as an intermediary component that receives outputs from multiple sensors and performs comparative analysis. This intermediary processes the sensor data, identifies normal outputs through comparison algorithms, and provides reliable measurement results even when some sensors fail, thus mediating between faulty sensors and the control system.
2Reliability
If multiple sensors are used for redundancy, then the system can tolerate individual sensor failures, but the complexity of the detection system increases
Solution Approach 1:
The patent merges multiple sensor outputs and the rotation angle calculator into an integrated detection system. By combining the main sensor, sub sensor, redundant sensor, and calculation logic into a unified system, the patent achieves high reliability while managing complexity through systematic integration rather than separate independent systems.
Solution Approach 2:
The rotation angle calculator serves multiple functions: it processes outputs from normal sensors, identifies abnormal sensors through comparison, and provides reliable measurement data. This multi-functional component reduces the need for separate systems for each function, thereby managing complexity while maintaining high reliability.
Data Source
AI summary
A detection unit has a rotation angle sensor including at least three detection elements detecting a change of physical quantity and outputting angle signals respectively corresponding to detection values of the respective detection elements. The detection unit also has a controller including an abnormality monitor monitoring the angle signals and identifying the respective angle signals either as a normal signal or an abnormal signal. The controller either outputs a value corresponding to at least one of two normal signals when two or more normal signals are identified or stops output regarding the detection signal when two or more normal signals are not identified.