Differential bridge type eddy current displacement sensor

Abstract

The invention discloses a differential bridge type eddy current displacement sensor. The differential bridge type eddy current displacement sensor comprises a signal processing device, a group of differential coaxial lines and a group of differential eddy current detection probes. Only one detection coil is arranged in each eddy current detection probe. The signal processing device comprises an excitation signal driving circuit, a balanced bridge circuit and a signal demodulation circuit. and the differential eddy current probes are installed on the two sides of a measured target, positive and negative probes respectively sense displacement change information on the two sides of the measured target to generate differential voltage signals, and analog voltage signals reflecting displacement changes can be obtained after signal demodulation. The balanced bridge only amplifies the impedance variable quantity of the detection coil and has higher resolution, and the temperature drift, interference noise and other properties of the two eddy current sensor probes are almost completely consistent, so that the differential bridge type eddy current displacement sensor has double sensitivity and extremely low noise and temperature drift, and the effect of reducing the size of the probe on the basis of improving the detection precision is realized.

Description

Technical field [0001] The present invention relates to a non-destructive detection device, and more particularly to a differential electrostatic call repellent displacement sensor for high-precision non-contact measurement of conductor displacement. Background technique [0002] In recent years, in the fields of mechanical, electric power, oil, aviation, aerospace, eddy current displacement sensors have many advantages such as non-contact, simple structural, high sensitivity, high frequency response, strong anti-malignant environment, not affected by non-metallic materials. It is widely used in the field of detection. [0003] The eddy current sensor works based on the impedance measurement principle. When the ambient temperature changes small in normal temperature, the output is less affected by the temperature, and the value of the measured displacement can be accurately reflected. When the ambient temperature is substantially deviated from normal temperature, the impedance of...

AI Technical Summary

Problems solved by technology

[0004] The impedance of the resistance, capacitance and detection coil in the circuit will change greatly in the high temperature environment, and the temperature will affect the temperature coefficient of resistivity of the common good metal conductors such as copper and aluminum, so the change of the environment temperature will seriously affect the eddy current displacement Sensor measurement results

When the ambient temperature is high, the impedance of the detection coil will change greatly due to the influence of temperature, resulting in a large drift of the measured signal

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