Research And Simulation On Mechanism Of Planar Two-Dimensional Time-Grating Displacement Sensor

With the introduction of the industrial 4.0 strategy and the concept of industrial internet,the global wave of industrial manufacturing upgrading and transformation has started.The demand for direct measurement of two-dimensional displacement will increase,such as CNC positioning table,microscope stage,etc.,which need precise positioning and orientation in two dimensions.Two-dimensional displacement measurement technology is not only an important feedback link of object plane motion,but also a key technology to achieve precise plane positioning.At present,multiple sets of high-precision onedimensional sensing systems can be used for combined measurement of two-dimensional displacement,but the measurement system is complex,the assembly precision and the cost is high.It is necessary to perform complex decoupling operation on the displacement signal,and signal processing is difficult.In order to meet the increasing demand for direct measurement of two-dimensional displacement,it is of great theoretical and practical significance to study the integrated two-dimensional displacement sensor with small integration,low cost,and two-dimensional displacement synchronous detection and direct decoupling measurement.Based on the time-grating sensing technology,a planar twodimensional time-grating displacement sensor capable of achieving two-dimensional displacement synchronous detection and direct decoupling measurement has been designed.The main research work of this topic is as follows:(1)Based on the coil constraint method for time-varying magnetic field,the spatial magnetic field distribution of the planar coil is deeply studied by the combination of theory and simulation.The coil structure of the two-dimensional time-grating coil is designed by analysing the sinusoidal requirements of standing wave and traveling wave.(2)Based on the traditional time-grating theory and two-dimensional displacement measurement requirements,the overall scheme of two-dimensional displacement direct decoupling measurement is proposed.On this basis,the planar two-dimensional time-grating structure which can realize synchronous detection for two-dimensional displacement and direct decoupling measurement is designed.The sensing mechanism of two-dimensional time-grating is deduced in detail and the two-dimensional displacement solution scheme using high-frequency clock pulse to interpolating phase difference is proposed.(3)Based on the two-dimensional time-grating structure design and excitation loading method,an electromagnetic simulation model of two-dimensional time-grating is established and finite element simulation is carried out.The electromagnetic simulation of the differential structure of the induction coil is carried out to verify the feasibility of decoupling on the structure and the induced signal of two-dimensional time-grating.The displacement measurement simulation is carried out for the overall structure and displacement measurement mechanism of the two-dimensional time-grating.It is verified that the twodimensional time-grating can simultaneously output single-frequency traveling waves for two directions.The main harmonic components of the displacement measurement error are determined and the reasons for the error in the model simulation are analyzed and summarized.(4)Based on the model error analysis and coil magnetic field distribution theory,the main parameters affecting the sensor's induced signal quality: coil width and air gap thickness are simulated numerically,and the simulation results are analyzed to provide a reference for the parameter control of sensor prototype development and experimental research.(5)Based on the simulation results and experimental requirements,an experimental platform for two-dimensional time-grating is built.The excitation signal and traveling wave signal are tested.The stability and precision experiment are carried out.The reasons for the error in the experiment were analyzed and corresponding solutions were proposed.The experimental results showed that the prototype realizes two-dimensional displacement synchronization detection and direct decoupling measurement.In summary,based on theoretical derivation,simulation verification and experimental research,the correctness and feasibility of the theoretical and structural design of planar twodimensional time-grating displacement sensor are verified,which lays a solid foundation for the subsequent study of higher-performance two-dimensional time-grating.