Torque Sensor Abnormality Diagnosis via Specific Waveforms
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Solution Overview
Problem
Existing sensor devices with dual systems cannot detect abnormalities in a sensor section when only one section is operational, leading to potential continuous inappropriate motor control in electric power steering apparatuses.
Innovation Solution
The sensor device outputs an abnormality diagnosis signal with specific waveforms to detect output abnormalities, allowing for continuous motor control even when only one sensor section is operational, and the motor control device updates the hold value to prevent inappropriate motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual system with two sensor sections is used to detect steering torque, then reliability is improved by having backup capability, but the ability to detect abnormalities in the remaining operational sensor section is lost when only one section is functional
Solution Approach 1:
The sensor device outputs an abnormality diagnosis signal in advance before actual sensor failure occurs. This preliminary action allows the control device to detect potential abnormalities in the operational sensor section by comparing the diagnosis signal against expected values, enabling proactive identification of issues while maintaining system reliability through the dual-sensor configuration
Solution Approach 2:
The system implements a feedback mechanism where the abnormality diagnosis signal from the sensor device is continuously monitored by the control device. The control device compares the diagnosis signal with reference values and provides feedback to determine whether the operational sensor section is functioning normally, thereby maintaining both reliability and abnormality detection capability
Data Source
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AI summary
A sensor device, such as a torque sensor, of a motor control device or an electric power steering apparatus includes a sensor section that detects a quantity of state of a detection subject and outputs a detection signal corresponding to the detected quantity of state. When receiving a specific trigger transmitted from an external device, the sensor section outputs an abnormality diagnosis signal, which is configured by a predetermined waveform and used for determining whether there is an output abnormality of the sensor section, and then outputs the detection signal.