Research On Pulse Eddy Current Testing System

With the advancement of science and technology,higher and higher requirements for the accuracy of metal plate thickness are put forward.An important technology in the manufacture and production of metal plate is the thickness measurement of metal plate.The problem of inconvenient and safe detection after metal plate rolling is compared with various detection methods,pulse eddy current testing technology has been used in this paper.The best method for the thickness of the metal plate has an irreplaceable advantage.In this paper,the principle of pulsed eddy current testing is mastered in the accumulation of a large number of literatures.The model of pulsed eddy current testing is established by using ANSYS Maxwell finite simulation software.The influence of parameter changes on the simulation results is analyzed,that is,the effect of the number of excitation coils and detection coils,the change in the excitation current,the change in the excitation voltage rise and fall time,and the change in the detection coil lift-off on the detected voltage peak.Through simulation,it can be obtained that the more the number of turns of the detection coil and the number of turns of the excitation coil,the larger the peak value of the detection voltage,and the higher the detection sensitivity.As the number of turns of the excitation coil increases,the peak time of the detection voltage also increases continuously;the larger the excitation current,the larger the peak value of the detection voltage,the higher the detection sensitivity;the smaller the excitation voltage rises and falls,the higher the peak value of the detection voltage,and the higher the sensitivity,the smaller the detection voltage reaches the peak time;as the detection coil lift-off increases,the peak value of the detection voltage gradually decreases,and the detection sensitivity is continuously lowered.The change of the detection coil lift-off only changes the peak value of the detection voltage,and does not change the time when the detection voltage reaches the peak value.The thinner the metal plate,the larger the peak value of the detection voltage,and the higher the detection sensitivity.Besides,the thinner the metal plate,the higher the resolution of the detection.Taking the simulation detection model as a reference,the experimental system of the pulse eddy current detection system is built.The hardware includes power amplification module,signal conditioning module,MCU hardware module and power supply module.The software design includes display resolution design,migration of graphical user interface emWin,porting of operating system ?C/OS-?,serial port printing and QT host computer design,study the relationship between the thickness of the metal plate and the peak value of the detection voltage,and compare and analyze the experimental test results with the simulation test results and the neural network test results.The results show that the value of the simulation test is always greater than the value of the experimental test.The thickness of the metal plate measured by the neural network is more accurate than the curve fitting to measure the thickness of the metal plate.In this paper,a total of 69 pictures,10 tables and 53 references.