Experiment Research Of Displacement Measurement System Based On Array Pulsed Eddy Currents Technology

Firstly,aiming at the ovality measurement in engineering practice,the displacement detection method of array pulsed eddy current was extended.In view of the phenomenon of crosstalk in the detection of pulsed eddy current,a system scheme based on time-sharing and series acquisition was proposed,and the corresponding hardware modules and host computer software were designed.Finally,the experimental demonstration and research were made.In the introduction of the principle of crosstalk,the equivalent model of the coil was set up from the angle of the conventional eddy current,the impedance analysis was carried out to expound the principle of the eddy current displacement measurement,and the interference phenomenon of the adjacent probe at the same time was introduced by the impedance analysis method.Then the principle of pulse eddy current detection was introduced,and the characteristics of the pulsed eddy current were compared with the conventional eddy current,and the simulation of the crosstalk of the adjacent probe excited by the pulsed eddy current was simulated.After analyzing the crosstalk phenomenon,a time-sharing and serial acquisition solution was proposed,and its feasibility was demonstrated by impedance analysis.The hardware circuit module is mainly aimed at the pulse signal generator circuit,the design of the time division circuit,the filter amplifier circuit of the detection signal and the selection of the device.At the same time,impedance analysis was made for the overshoot voltage generated in the pulse excitation circuit,and solutions were put forward.Then,the parameters of the acquisition card were introduced.The software part first introduce the function and interface of the software,and then introduced the calibration algorithm and trigger mode of the channel,the generation and elimination of accumulation error,the difference and demarcation of the sensor.Finally,the measurement experiment and the accuracy evaluation of the system were introduced.An improved method was proposed for the test results.Finally,the curve fitting algorithm of ovality was introduced briefly.The system developed in this paper not only realizes the influence of the sulfa crosstalk in the detection of the pulsed eddy current array,but also simplifies the hardware circuit structure of the multi channel signal acquisition.Meanwhile,the author developed a set of corresponding host computer software corresponding to the hardware system,and realized a complete displacement measurement system with independent intellectual property rights.The innovation is based on the method of time-sharing and collection in series.This method is the analogy method of time-sharing acquisition method.The author makes a careful analysis and demonstration of various practical problems existing in the time sharing incentive and puts forward the corresponding solutions.Finally,the whole system framework is built.