Research On Temperature Compensation And Performance Optimization Technology Of Tunnel Magnetoresistance High Precision Accelerometer

With the continuous development of microelectromechanical systems,tunnel magnetoresistance sensors has emerged.Combined with high-sensitivity tunnel magnetoresistance sensors,high-precision acceleration measurement can be achieved.Tunnel magnetoresistance accelerometers have the advantages of small size,high precision and integration,and have broad application prospects in inertial navigation,automotive industry,gravity field detection and other fields.Tunnel magnetoresistance accelerometers measure acceleration through force,magnetic and electrical multi-physical field coupling,and the effect of temperature is one of the key factors restricting its performance;at the same time,for magnetic sensing,the environmental magnetic field also affects acceleration measurement has a huge impact.Therefore,exploring how to improve the temperature stability of the tunnel magnetoresistance accelerometer and suppress the interference of the external magnetic field on the tunnel magnetoresistance accelerometer has important practical value and engineering significance for the realization of high-performance tunnel magnetoresistance accelerometer development.Based on the study of the measurement principle of the tunnel magnetoresistance accelerometer,the temperature compensation technology and the environmental magnetic field shielding technology are studied in this thesis.Firstly,on the basis of studying the existing temperature compensation technology,the software compensation method is used to realize the temperature performance compensation of the tunnel magnetoresistance accelerometer.The compensation algorithms include polynomial fitting,Elman neural network,self-feedback Elman neural network,etc.,and the particle swarm optimization algorithm is used to select network parameters,which improves the convergence speed and globality of the network.After analyzing and comparing the advantages and disadvantages of the algorithms through simulation,the temperature compensation circuit system is designed from both hardware and software aspects.Secondly,by analyzing the existing magnetic shielding technology,a hollow shell based on high permeability permalloy material is designed for the tunnel magnetoresistance accelerometer as a magnetic shielding structure.Use Ansys to perform finite element simulation of the magnetic shield,and optimize the structural size of the magnetic shield,enhance the magnetic shielding efficiency,and improve the anti-interference ability of the accelerometer by simulating the influence of thickness and aperture size on the shielding effectiveness of the magnetic shield.Finally,in order to verify its performance,a system object is designed and produced.The test results show that after compensation,the full temperature zero bias range,scale factor temperature coefficient and nonlinearity of the tunnel magnetoresistance accelerometer are reduced from 186mg,730ppm/℃,31428ppm to 13.6mg,185ppm/℃,1695ppm,respectively.The temperature stability is greatly improved,which proves the correctness and effectiveness of the compensation method.At the same time,the experimental results of the magnetic shield show that the device can suppress the environmental magnetic field by 99.4%,which significantly improves the anti-interference performance of the tunnel magnetoresistive accelerometer.This provides strong technical support for the development of high-performance tunnel magnetoresistance accelerometers.