Research On Cylindrical Time-grating Angular Displacement Sensor Based On PCB Technology

Sensor technology is one of the three modern information technology,with the progress of human society,the demand for precision measurement is increasing in all walks of life,displacement sensor plays an important role in precision manufacturing,national defense,industrial production.Time-grating is a kind of displacement sensor "measuring space by time" proposed by the author's team.However,the current electromagnetic induction timegrating angular displacement sensors has the following problems: First,early electromagnetic induction type time-grating when using special motor angular displacement sensor,and machining parts in the stator tooth structure,and on the tooth space uniform winding excitation and induction coil,and this makes the sensor windings poor consistency alveolar effect,has certain influence the uniformity of magnetic field distribution,which may effects the precision of the sensor;Second,the early electromagnetic induction timegrating angular displacement sensor needs to design a groove structure on the stator to solve the problem of coil installation,which makes the winding time grid sensor installation inconvenient in some limited working space,to a certain extent limited its application scenarios;Third,the planar PCB magnetic field type time-grating angular displacement sensor solves the problem that the winding type time grid tooth groove structure effects the magnetic field distribution and the windings are inconsistent,but it is difficult to apply to some hollow measured objects,and it is difficult to install the stator and rotor alignment.Based on the above analysis,this paper proposes a cylindrical time-grating angular displacement sensor based on PCB technology.This paper mainly studies the following aspects :(1)Based on Biot-Savart law,the magnetic field distribution law of the energized coil in cylindrical space is derived mathematically,which is used as the basis for the design of the sensor structure;(2)The equivalent magnetic circuit model is established and the working principle of the sensor is analyzed.(3)The influence of machining and installation deviation of cylindrical PCB on sensor measurement error is analyzed theoretically;(4)Design sensor simulation model and carry out electromagnetic finite element simulation analysis;(5)Take STM32H743 microcontroller as the core to design the corresponding hardware system and software system;(6)Prototype test and error analysis.Based on the above work,the cylindrical time-grating angular displacement sensor based on PCB technology in this paper has the following advantages :(1)PCB technology is used to make the excitation coil better consistency,and the coil shape can be precisely controlled,so as to obtain a more ideal time-varying magnetic field,so as to improve the measurement accuracy of the sensor;(2)Theoretical analysis of the fabrication and fitting error of flexible PCB tape provides theoretical guidance for the practical installation and application of sensor;(3)The signal processing system with STM32H743 microcontroller as the main control chip has lower cost than the previous signal processing system of time gate sensor;(4)The coil required by the electromagnetic induction sensor is distributed in the flexible PCB belt in this design.It is not necessary to provide a specific shape of the iron core to place the metal coil,which is easy to achieve embedded measurement.The experimental results show that the resolution of the sensor is 1.6 ",and the error within the whole measurement range is less than 0.017°.To sum up,this paper successfully designs a process of cylinder type grating angular displacement sensor based on PCB,the finite element simulation and the prototype experiments are proved that the theory of cylindrical magnetic field distribution,the correctness of the measurement principle of sensor and analysis results of prototype precision experiments verify the PCB fabrication and installation deviation affect measuring accuracy analysis is correct.At the same time,the rationality of sensor structure design is verified.