Research On Error Tracing And Calibration Method Of Embedded Time Grating Angular Displacement Sensor

With the development of national science and technology,higher requirements are put forward for the manufacturing industry.In the process of equipment processing,high-precision detection equipment is indispensable.As a key component of precision measurement in advanced manufacturing and intelligent manufacturing,precision measurement instrument directly determines the level of mechanical manufacturing.The embedded time-grating angular displacement sensor is a new type of sensor which is designed based on the time-grating technology.The sensing mechanism of embedded time-grating has been studied in the early stage,but the optimization design of sensor structure and the improvement of sensor measurement accuracy are still the key issues in the sensor research.Based on this,this paper studies the error tracing and calibration method of the embedded time-grating angular displacement sensor.The main research contents of this paper are as follows:1)Based on the space-time transformation theory and aiming at the time-grating sensing mechanism,the key problem of measuring the embedded time-grid angular displacement sensor is to construct the space-time transformation coordinate system of uniform motion.Based on this,a uniform rotating magnetic field is constructed by means of time-orthogonal excitation signal and space-orthogonal mechanical structure,and a space-time transformation coordinate system with uniform motion is formed.2)In order to clarify the error law of the embedded time-grating angular displacement sensor,the error of the sensor is traced.Based on the mechanism of the sensor signal and the mechanical structure of the sensor,the electrical error and the installation error are traced.The measurement error model caused by zero error,orthogonal error and dc component error under electrical error is established.The influence of air gap variation during installation,radial installation and axial installation of measuring head on measuring accuracy of sensor is analyzed,and the relevant mathematical model is established.A mathematical model for tracing the electrical and installation errors of the embedded time-grating angular displacement sensor is constructed.3)Aiming at the short period error calibration of the embedded time-grating angular displacement sensor,the calibration method of the extreme learning machine(ELM)is proposed and compared with the Fourier approximation method.In order to improve the overall measurement accuracy of the sensor,a step-by-step error calibration model is proposed by combining the Fourier approximation method,adaptive mean square deviation threshold method,extreme learning machine and particle swarm optimization(PSO)algorithm.The system error,gross error and random error of the measurement are compensated step by step,and finally the high-precision calibration of the sensor is realized.4)An experimental platform is built to study the error tracing model and calibration model.The results of error tracing experiment show that the electrical error mainly causes the short period first order error,the short period quadric error and the constant value error;the installation error mainly causes the short period first order error,the short period quadric error and the long period first order error.The experimental results of error calibration show that the short period error of the sensor is up to 4.0 "after the calibration of the extreme learning machine,which is more effective than the Fourier approximation method for the calibration of the short period error;after the step-by-step calibration,the final accuracy of the sensor measurement is up to 0.9",which has important application value for the realization of the high-precision measurement of the embedded time-grating sensor.In conclusion,on the basis of the previous research of time-grating sensor in the research group,this paper has carried out the research on the error tracing and calibration method of embedded time-grating sensor,analyzed the electrical and installation errors of the sensor,and carried out the research on Fourier approximation,extreme learning machine and step-by-step calibration method,and carried out the experimental verification.Theoretical analysis and experimental results show that the research on the error tracing and calibration of the embedded time-grating angular displacement sensor is of great practical significance for optimizing the sensor structure and improving the measurement accuracy.