Resolver Fault Detection via Common Mode DC Bias
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Solution Overview
Problem
Aircraft sensor systems, particularly those using resolvers, synchros, RVDTs, and LVDTs, face challenges in detecting and mitigating short circuits and open circuits within the sensors and wiring harnesses, which can impact system reliability and are difficult to detect due to voltage variations and complex interfaces.
Innovation Solution
A sensor interface design that employs a common mode DC bias to facilitate the detection and quantification of faults, using a controller with DC voltage bias networks and fault sense circuits to identify and mitigate short and open circuits without affecting normal measurement operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex sensor interfaces are used to ensure robustness over all 4 quadrants, then measurement reliability is improved, but fault detection capability deteriorates due to difficulty in identifying short circuits and open circuits
Solution Approach 1:
The patent applies preliminary action by injecting test signals before normal operation to detect potential faults. The system performs self-tests by injecting known test signals into the sensor interface circuitry and monitoring the responses, allowing faults to be detected before they affect actual sensor measurements during aircraft operation.
Solution Approach 2:
The patent uses an intermediary approach by introducing a dedicated fault detection circuit that acts as a mediator between the sensor interface and the control system. This separate circuitry injects test signals and analyzes responses without interfering with normal sensor operation, enabling independent fault detection while maintaining measurement reliability.
2Reliability
If redundant sensor systems are implemented to mitigate fault impact, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a sensor interface that performs multiple functions: normal sensor signal conditioning and fault detection. The same interface circuitry handles both operational signals and test signal injection, eliminating the need for completely separate redundant systems while maintaining reliability through integrated self-diagnosis capabilities.
Solution Approach 2:
The patent implements self-service through automatic fault detection and identification within the sensor interface. The system monitors its own health by injecting test signals and analyzing responses, automatically identifying faults without requiring external monitoring systems or redundant sensor arrays, thereby reducing overall system complexity.
3Adaptability or versatility
If phase sensitive or synchronous demodulation is used to operate over multiple quadrants, then angular measurement capability is improved, but circuit complexity increases making fault detection more difficult
Solution Approach 1:
The patent applies preliminary action by performing fault detection through test signal injection before normal angular measurement operations. The system validates the integrity of phase-sensitive demodulation circuits by injecting known test signals at specific angles and verifying expected responses, enabling fault detection in complex multi-quadrant operation without requiring additional circuitry.
Data Source
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AI summary
Embodiments herein relate to a sensor fault measurement system. The system includes a sensor having a primary winding, a first secondary winding and a second secondary winding and a wiring harness operably connected to the primary winding, first secondary winding and second secondary winding of the sensor. The system also includes a controller operably connected to the wiring harness. The controller includes a bias network configured to apply a common mode DC voltage bias of opposite sign to the first sensor output and the second sensor output respectively, and a fault sense circuit configured to monitor the DC voltage bias on first sensor output and the DC voltage bias on second sensor output, and identify a sensor fault if at least one of the DC voltage bias on first sensor output and the DC voltage bias second sensor output is impacted beyond a selected threshold.