Influence Of Adhesive Bonding On Zero Bias Of Miniature Accelerometers

Accelerometer is the core element of inertial navigation system,its performance directly affects the navigation accuracy of inertial navigation system.At present,only by improving the accuracy of the parts manufacturing is not enough to achieve the purpose of improving the accelerometer performance,and through improving the assembly process is a way to improve the performance of the accelerometer.In general,the magnitude of the zero bias error can reflect the stability of the accelerometer.The greater the error of the zero bias,the worse the stability of the accelerometer,so research the influence of each factor on the zero bias error of the accelerometer is important to improve the zero bias stability of the accelerometer.According to the working principle and structure of a certain type accelerometer,the transfer function of the accelerometer is deduced,and the error model of the accelerometer is established.It is determined by analyzing that the assembly error of adhesive layer in the accelerometer is one of the main factors leading to the error of the zero bias of the accelerometer.According to the assembly characteristics of the certain accelerometer,the main way of connection of the parts in accelerometer are adhesive bonding.The assembly process is done by manual.The following several errors are caused by manual: thickness error,contact area error and overflow quantity error of adhesive layer,as well as the position,size and quantity difference of bubbles contained in adhesive layer.Based on this,the ABAQUS finite element simulation software was used to establish the accelerometer error model.The influence of the assembly error of the adhesive layer on the zero bias error of the accelerometer was analyzed.The results show that the zero bias error of the accelerometer is greatly affected by the thickness error,contact area error and the spillage amount of adhesive layer,and the zero bias error caused by the spillage amount of adhesive layer at different positions can be compensated.Therefore,the thickness error and contact area error of the adhesive layer should be strictly controlled during the assembly process.In addition,the bubble in the adhesive layer will also have a certain impact on the zero deviation of the accelerometer.Since the bubble contained in the adhesive layer will reduce the adhesive strength of the adhesive layer,thus reducing the reliability of the accelerometer.Before the assembly process,it is suggested that the bubble in adhesive layer should be removed by the vacuum chamber.The zero bias hysteresis loop is caused by the working temperature-changing,which causes the zero bias hysteresis loop of the accelerometer can’t be accurately compensated,thereby reducing the measurement accuracy of the accelerometer.In this paper,the influence of the elastic modulus,thermal expansion coefficient,poisson’s ratio,creep rate and geometric error on the zero bias hysteresis loop is studied from the material properties and geometric error of the adhesive layer.The results show that the elastic modulus,the creep rate and the unilateral overflow of the adhesive layer have a great influence on the zero bias hysteresis loop.The research in this paper provides a theoretical basis for selecting the appropriate adhesive and improving the assembly process.