Research On Two-dimensional Time-gate Displacement Sensing Method And Device Based On Alternating Magnetic Field

With the promulgation of the national "14th Five Year Plan",the country urgently needs to break through the foreign blockade in the research and development of many high-end and cutting-edge equipment,among which the precise two-dimensional displacement sensing technology has always been the core technology urgently needed to master.Currently,the measurement accuracy of popular two-dimensional displacement sensors heavily relies on ultra-precision machining processes,resulting in restrictions on the improvement of measurement accuracy of two-dimensional sensors;As well as a twodimensional measurement system composed of multiple sets of one-dimensional sensors,a variety of errors are introduced,resulting in a reduction in the accuracy of the entire system.Therefore,in order to meet the growing demand for two-dimensional high-precision measurement,research is carried out on two-dimensional displacement measurement technology that does not rely on processing technology,high precision and large range.Based on time-gate sensing technology,this paper has conducted research on planar twodimensional time-gate displacement sensing methods and devices based on alternating magnetic fields.The main research work is as follows:(1)By analyzing the spatiotemporal conversion theory of the time grid,the basic principle of mutual conversion between space measurement and time measurement is derived,and the magnetic field generated by the closed rectangular coil after the alternating current is analyzed combined with the principle of electromagnetic induction is analyzed,and a theoretical model is established.In this paper,a two-dimensional magnetic field coding method based on the uniform arrangement of excitation windings on the plane is proposed,and an alternating magnetic field is generated by the closed rectangular excitation windings arranged spatially in the form of a chess board,and a reference coordinate system between the displacement and the time reference is established.Then,the sinusoidal induction winding is used to generate a traveling wave signal through combined measurement,so that the induction winding can directly decouple the magnetic field and complete the measurement of the two-dimensional displacement.By controlling hardware factors such as the shape and arrangement of the induction winding,the induction winding forms a differential sensing structure in space,suppresses the error introduced by external factors,and improves the measurement accuracy of the sensor.Finally,the principle derivation and theoretical error model of the planar two-dimensional time-gate displacement sensing method based on alternating magnetic field are completed.(2)The model of the plane two-dimensional time gate displacement sensor is modeled in 3D,and then the model related parameters of the sensor are set in the electromagnetic field simulation software and the magnetic field finite element simulation is carried out.According to the simulation results,the control variable method is used to analyze the errors introduced by different air gap heights and deflection angles of different planes between the moving ruler and the fixed ruler,and the sensor model is optimized to analyze the simulation error in the two-dimensional sensor.(3)Using PCB technology to fabricate a planar two-dimensional time grating displacement sensor prototype,and according to the design requirements of excitation sources and signal processing circuits,using FPGA core boards to establish a twodimensional time grating displacement measurement electrical system.(4)Establish an experimental platform for planar two-dimensional time grating displacement sensor,design a specific experimental scheme,and test the sine/cosine excitation signal generated by the sensor and the output sensing signal.After that,validation experiments were conducted on the stability of two-dimensional sensors,intra polar accuracy,and full range accuracy,analyzing the measurement error results in the experiments,and then performing harmonic correction on the experimental results.Finally,it is concluded that the sensor has a full range of 72mm×72mm measurement,the range of measurement error in the X direction before correction is-59.1μm～44.85μm.The range of measurement error in the Y direction is-31.95μm～58.35μm;the measurement error range in the X direction after correction is-11.1μm～11.45μm.The measurement error range in the Y direction is-11.7μm～12.6μm。...