Research On Miniaturized Electromagnetic Induction Angle Displacement Sensor Based On PCB Technology

With the continuous expansion of the global industrial field,the trend of the traditional manufacturing industry towards automation and intelligence is gradually rising.as the position in the full-closed-loop control system,The displacement sensor that feeds back the core components plays a decisive role in the working performance of the entire control system.After years of development,electromagnetic induction angular displacement sensors are widely used in industrial and military industries because of their advantages such as high stability,good reliability,and low requirements for the working environment.Traditional electromagnetic inductive angular displacement sensors,such as rotary transformers and inductive synchronizers,fail to meet the development needs of the industrial automation field due to factors such as volume and weight,especially the development needs of the robot industry.Therefore,many new types of disc angular displacement sensors have been developed rapidly,such as Zettlex IncOder encoders,Netzer rotary encoders,Yingdong Gaoke rotary encoders,etc.Among them,the Zettlex IncOder encoder is an electromagnetic induction sensor,which has a higher level of integration than a disc-type induction synchronizer,so it has been widely used in applications where the volume and weight of the sensor are relatively sensitive.In view of the shortcomings of traditional electromagnetic inductive angular displacement sensors and the development needs of new types of angular displacement sensors,this paper combines today's more mature PCB(Printed Circuit Board)technology to carry out a research on a miniature electromagnetic induction angular displacement sensor based on PCB technology.The main research contents and results of this article are as follows: Based on the simulation results,the design and manufacturing of the prototype was carried out.Based on the simulation results and analysis of four sensor structures,the final basic structure of the prototype is: the stator contains three sets of inner coils,inner and outer ring coils and two sets of sinusoidal coils,and the rotor contains inner and outer copper foil arrays.In order to achieve absolute displacement measurement,the number of cycles of the inner and outer ring dual-channel sensing units differs by one.The stator and rotor of the prototype are manufactured by PCB process.(1)According to the measurement principle and research status of mainstream sensors,combined with the theory of electromagnetics,the principle of time-varying magnetic field generation and the constraining method of plane magnetic field are studied,which lays the foundation for the research of miniaturized electromagnetic induction angular displacement sensor.(2)Research on the theoretical model of miniaturized electromagnetic induction angular displacement sensor.According to the relationship between the change of the magnetic flux in the induction coil and the measured displacement,the planar excitation coil and the induction coil are accurately designed and arranged,so that the desired functional relationship between the output signal of the induction coil and the measured displacement is achieved,thus the structure of the sensor Design provides theoretical support.(3)A structural design and simulation study of a miniaturized electromagnetic induction angular displacement sensor was carried out.Three different types of angular displacement sensor structures were designed,and the finite element analysis was carried out to verify the feasibility of the sensor structure from the simulation level.(4)Based on the simulation results,the design and manufacturing of the prototype was carried out.Based on the simulation results and analysis of four sensor structures,the final basic structure of the prototype is: the stator contains three sets of inner coils,inner and outer ring coils and two sets of sinusoidal coils,and the rotor contains inner and outer copper foil arrays.In order to achieve absolute displacement measurement,the number of cycles of the inner and outer ring dual-channel sensing units differs by one.The stator and rotor of the prototype are manufactured by PCB process.(5)The experimental research of the sensor prototype was carried out.A set of angular displacement experimental platform compatible with the sensor diameter of 40 mm ~ 200 mm was designed and built,and preliminary experiments and improvement experiments were carried out on the prototype.Preliminary experiments show the feasibility of the sensor structure,but when a small-sized sensor prototype uses a signal processing circuit based on the phase discrimination principle,the output signal is weak and cannot be measured.Therefore,the sensor prototype uses a circuit based on the amplitude discrimination principle for signal processing,and increases its output signal strength by increasing the excitation frequency and the use of a resonant circuit;Improved experiments show that the original error of the whole prototype of the sensor prototype with a diameter of 80 mm and a thickness of 26mm(including the housing)is-70"~+80",and the short period original error is-40"~+10".