Design And Development Of Eddy Current Displacement Switch Sensor Based On Temperature Invariant Phenomenon

For displacement measurement in engineering,the sensors include the grating displacement sensor,the differential pressure displacement sensor,the resistance displacement sensor,the photoelectric code displacement sensor,eddy current displacement sensor,etc.Among them,the eddy current displacement sensor is widely used in engineering fields such as detecting displacement,thickness,and defects due to its simple structure,non-contact type,and high cost performance.As an inductive eddy current sensor,the eddy current sensor has strong sensitivity to the ambient temperature,so it is necessary to study and design a temperature-resistant eddy current sensor to enhance the adaptability of the eddy current sensor to the ambient temperature.In this thesis,a combination of finite element simulation analysis and experimental verification is used to design a new eddy current displacement switch sensor and the system including the eddy current sensor probe,signal circuit analysis and processing,and eddy current sensor signal data collection are build up.Under the condition of ensuring the measurement accuracy,the temperature resistance of the eddy current sensor has been greatly improved.This thesis mainly focuses on the following aspects:(1)the dual coil probe of eddy current displacement swich sensor is designed and optimized based on tempreture invarience phenomenon.A finite element model of a dualcoil probe for displacement measurement was established,and the effects of the geometrical parameters of the dual-coil on the characteristic magnetic differential signal under the different ambient temperature were studied.On this basis,a simulated output magnetic signal under a specific structure was found with the change trend of the ambient temperature,the phenomenon that the curves under different ambient temperatures intersect in an area is verified,and this phenomenon is called as the temperature invariant phenomenon.After,the further simulation and analysis of the position of the temperature invariant region,the optimization parameters of the coil probe when the switch detection distance of the eddy current sensor is 10.0mm are proposed.(2)A temperature-resistant eddy current displacement switch sensor is Design After the overall experimental scheme is proposed,the temperature-resistant eddy current displacement probe is manufactured,the dual-coil output signal conditioning circuit is designed,the magnetic differential signal of the temperature invariant point is converted into a voltage signal by signal conversion circuit,and the single-chip communication technology is to collect and display the eddy current sensor signal.finally,the all modulaus are integrated.(3)High and low temperature experimental testing is carried for the temperatureresistant eddy current displacement switch sensor and the error is analyzed in detail.The purpose of the high and low temperature test experiment was determined.Through the debugging of the high and low temperature test platform,the coil output test,resistance test,excitation voltage test and other experiments of the eddy current displacement switch sensor were carried out,which made preparation for the subsequent high and low temperature test experiment.By collecting experimental data,the switching performance of the temperature-resistant eddy current displacement switch sensor system is studied and analyzed,and a comprehensive error summary is made for the experimental results.