Research On Absolute Time-grating Angular Displacement Sensor Based On Planar Time-varying Magnetic Field

With the rapid development of industrial technology,the requirement of precision displacement measurement technology is getting higher and higher.As one of the three foundations of modern information technology,the performance of sensor technology is closely related to the measurement results.Time grating displacement sensor is a self-developed displacement sensor,which realizes the measurement of space by time.Electromagnetic induction time grating angular displacement sensor belongs to time grating displacement sensor,which has strong anti-interference ability and high reliability.However,the traditional electromagnetic induction grating angular displacement sensor manufactured by manual winding has poor consistency.And it is easily disturbed by human factors,which affects the measurement accuracy of the sensor.In some specific situations,absolute sensors with the characteristics of direct reading information,power-off protection and high productivity are needed to complete displacement measurement.At present,the measurement methods of time grating angular displacement sensor mainly include incremental measurement and absolute measurement.It is still necessary to strengthen the research of absolute measurement.Based on the above reasons,a method of constructing planar time-varying magnetic field is proposed.Combining this method with the measurement theory of time grating angular displacement sensor,an absolute time grating angular displacement sensor based on planar time-varying magnetic field is developed.In this paper,the basic theory of time-grating angular displacement sensor is briefly introduced,and a method of constructing planar time-varying magnetic field is proposed.The induction coil is placed in the magnetic field constructed by this method,and the relationship between induction electromotive force and displacement in the induction coil is deduced.Combined with the working principle of time-grating angular displacement sensor,the basic measuring principle of time-grating angular displacement sensor based on planar time-varying magnetic field is deduced,and the absolute displacement measurement is realized by combining two precision units.Ansoft Maxwell 16.0 is used to establish the principle model of the sensor and simulate the electromagnetic field.After analyzing the simulation results,the structure parameters of the sensor are determined.The corresponding signal processing circuit of the sensor is designed to provide the required excitation signal for the sensor,and the output signal of the sensor is converted into angular displacement information.A prototype of dual precision units time grating angular displacement sensor with pair poles of 53 and 72 is developed by PCB technology.The experimental platform is set up,and the principle experiment and performance test experiment of the sensor prototype are carried out.In the range of 0o to 360o for the prototype of angular displacement sensor,the original measurement error of 72 pairs of polar sensor units is relatively small,and the range of variation is ±20?.The original measurement error range of 53 pairs of polar sensing units is ±25?.The experimental results verify the feasibility of the absolute measurement method of double precision units.In summary,theoretical model deduction and analysis,structural design and experimental research are carried out in this paper.The correctness of the principle of the sensor system and the comprehensive performance of the system are verified.The main sources of errors are analyzed,which provides a basis for subsequent sensor research.