| 摘要 |
PROBLEM TO BE SOLVED: To perform accurate failure diagnosis based on an AC phase component and a DC voltage component and further to increase a large dynamic range of a detection signal to improve detection sensitivity, in a torque sensor having functions for temperature compensation and failure diagnosis with a simple constitution. SOLUTION: A temperature drift compensation resistance element is connected to first and second coils arranged to generate an impedance change having a reverse characteristic to a torque to be detected. An AC signal for coil excitation is generated based on a clock signal generated from a microcomputer. A difference between an output AC voltage of each coil and an AC voltage for coil excitation is determined by a differential amplifying circuit, and the difference is sampled respectively in each integer-fold period of the clock signal by the microcomputer. Two kinds of torque detection data having mutually reverse characteristics are obtained by the sampling. When an addition value of the two kinds of torque detection data is out of a prescribed range, it is diagnosed 'which coil is abnormal', from the AC phase component and the DC voltage component. COPYRIGHT: (C)2011,JPO&INPIT
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