Fault detection in variable differential transformer sensors based on zero-crossings of signals
AssigneeThe Boeing Company
InventorRichard J. Wingerter
Life of this patent
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Abstract
Systems and methods of detecting failures in an assembly that uses a variable differential transformer sensor. In one embodiment, a signal processor receives an excitation signal applied to the sensor, and detects a zero-crossing of the excitation signal. The signal processor receives an output signal of the variable differential transformer sensor in response to the excitation signal, and detects a zero-crossing of the output signal. The signal processor detects a fault in the assembly responsive to a determination that the zero-crossing of the output signal is separated from the zero-crossing of the excitation signal by more than the detection threshold.
Claims20
A system configured to detect a failure in an assembly (300, 700) that uses a variable differential transformer sensor (320, 720), the system comprising:
- a signal processor (310) connected to an Alternating Current “AC” voltage source (312) that provides an excitation signal (352) to the variable differential transformer sensor, and connected to outputs (336-337) of the variable differential transformer sensor, the signal processor comprising:
- a zero-crossing monitor (316) that receives (402) the excitation signal applied to the variable differential transformer sensor, detects (404) a zero-crossing of the excitation signal, receives (406) an output signal (353) of the variable differential transformer sensor in response to the excitation signal, and detects (408) a zero-crossing of the output signal;
- and
- a fault detector (318) that detects (412) a fault in the assembly that uses the variable differential transformer sensor responsive to a determination that the zero-crossing of the output signal is separated from the zero-crossing of the excitation signal by more than a detection threshold.
A method (400) of detecting a failure in an assembly that uses a variable differential transformer sensor, the method comprising:
- receiving (402), in a signal processor, an excitation signal applied to the variable differential transformer sensor from an Alternating Current “AC” voltage source;
- receiving (406), in the signal processor, an output signal of the variable differential transformer sensor in response to the excitation signal;
- detecting (404), at the signal processor, a zero-crossing of the excitation signal;
- detecting (408), at the signal processor, a zero-crossing of the output signal;
- and
- detecting (412), at the signal processor, a fault in the assembly that uses the variable differential transformer sensor responsive to a determination (410) that the zero-crossing of the output signal is separated from the zero-crossing of the excitation signal by more than a detection threshold.
A system comprising:
- a threshold detector (802) that uses a test process (900) to determine a detection threshold for detecting a fault in an assembly having a variable differential transformer sensor (320, 720), wherein the threshold detector receives an excitation signal (352) applied to the variable differential transformer sensor, and receives an output signal (353) of the variable differential transformer sensor in response to the excitation signal;
- wherein the test process includes:
- detecting (902) zero-crossings of the excitation signal and zero-crossings of the output signal during a non-failure state of the variable differential transformer sensor;
- determining (904) a worst case separation between the zero-crossings of the excitation signal and the zero-crossings of the output signal during the non-failure state;
- detecting (906) the zero-crossings of the excitation signal and the zero-crossings of the output signal during a failure state of the variable differential transformer sensor;
- determining (908) a best case separation between the zero-crossings of the excitation signal and the zero-crossings of the output signal during the failure state;
- and
- selecting (910) the detection threshold to be between the worst case separation and the best case separation.
Dependencies are inferred from the claim text.