The Time-Sharing Incentive Based Method Of Pulsed Eddy Current Displacement Sensor Array

Displacement measurement is widely used in engineering applications.Pulsed Eddy current displacement sensor is a new kind of displacement sensor technology,with periodic pulse square wave instead of the sine and cosine excitation signal in the conventional eddy current displacement sensor,resulting in instantaneous eddy current magnetic field,which has the advantages of fast response and sensitivity.In the case of dense multi-point measurement,the conventional eddy current displacement sensor is close to each other and produces electromagnetic crosstalk,which affects the measurement result.The use of time-sharing mode can eliminate the crosstalk between pulsed eddy current displacement sensor array,and has good engineering application prospect.Based on the analysis of the basic theory of pulse eddy current displacement sensing method,the sensing method of pulse eddy current displacement measurement with coil excitation and Hall sensor is proposed.The feasibility of the displacement measurement sensor structure is analyzed from the finite element analysis software and the experiment,and the pulse eddy current displacement measurement sensor is linearly modified by the software correction method.Aiming at the problem of electromagnetic crosstalk caused by the arrangement of the conventional eddy current displacement sensor,an array pulse eddy current displacement measurement method based on time-dependent excitation is proposed,and an array pulse eddy current displacement system is designed,which includes hardware circuit and software algorithm.Wherein the hardware circuit comprises a generation of a pulse square wave excitation signal,an excitation signal power amplifying circuit,a differential output amplifying circuit,and a multi-channel switching circuit;The software algorithm includes pulse square wave signal generation based on STM32,channel address switching,trigger acquisition,serial communication algorithm based on LabVIEW,data linear fitting and data linearization outputting based on look-up table.Finally,the significance of pipe straightness and ellipticity measurement is summarized.The method of array pulse eddy current displacement measurement based on time sharing excitation is used to measure the straightness and ellipticity of tubing,and the ellipticity and straightness measurement algorithm are given.The results show that the pulsed eddy current displacement sensing technology can achieve dense multi-point displacement measurement,and has a wide range of applications in array line displacement sensing and surface displacement sensing applications.