Research On Inductive Time-grating Angular Displacement Sensor

Measurement technology is an important means for people to know the world.Displacement measurement is the most basic and widely used measurement in modern industrial measurement technology.From the visual measurement to the simple measurement,and then to the precise measurement,the measurement requirements of the displacement sensor are higher and higher.Due to the advantages of the absolute measurement,such as direct readability,high productivity,and power-off protection,the application is more and more extensive,which has become an important trend of displacement measurement,and also one of the key research directions of time grating research team.As for the current absolute measurement method of time grating,whether it is the combination of "coarse machine + fine machine" or "fine machine" + "fine machine",there are obvious limitations: the combination measurement method needs to establish two sets of independent sensing and measuring units,which will cause the sensor volume to be too large,and it is difficult to ensure that the two sets of sensing units will not affect each other.At present,the current construction of time grating sensor units is mostly based on magnetic field coupling,which often requires the establishment of special structures of sensors to satisfy the design of multiple sensing units,while the possibility of constructing the sensor unit through the electrical parameters of time grating itself is ignored,and there is little research on this direction.In view of this,this paper based on the idea of using the electrical parameters(inductance change)of the time grating itself to construct the sensor unit,the research work of the inductive time grating angular displacement sensor which can realize the absolute angular displacement measurement is carried out.The main contents of this paper are as follows:(1)The theory of time-space coordinate conversion,the mechanism of time grating with variable reluctance and the method of traveling wave synthesis are studied in depth,and the theoretical model of inductive time grating angular displacement sensor is established.(2)The electromagnetic field simulation software is used to establish the simulation model of the inductive time grating angular displacement sensor.Two different structures of the model are simulated.The coil design law is summarized and the influence of stator cogging on measurement accuracy is analyzed.According to the simulation results,a 45 pole type I inductive time grating angular displacement sensor prototype is designed,and a type II sensor prototype is designed as its derivative series using PCB.(3)According to the relationship between the change of inductance and air gap of the sensor,the bridge conditioning circuit and the subsequent signal processing circuit for the inductive time grating angular displacement sensor are designed to convert the change of inductance into position information that can be read.(4)The experiment platform is built,and the principle experiment and precision experiment are carried out for the designed sensor.The experimental results show that within the measurement range of 360°,the error range of the sensor ? is-30?~40?,the error range of the sensor?is-10?~10?.In conclusion,a new scheme of traveling wave formation is proposed by analyzing the change process of the gate's own inductance and combining with the impedance bridge.Based on this scheme,the sensor structure of inductive time grating angular displacement sensor is designed.By reducing the number of windings,the influence of parasitic capacitance formed between multiple windings with the same tooth on the measurement is avoided.In this paper,a new idea has been developed for the research of time grating,which has important theoretical and practical significance for its absolute measurement and electric parameter sensing.