Research On The Influence Of Assembly Factors On Photoelectric Accelerometer's Bias

Photoelectric accelerometer, which is widely used in aviation, marine and other military areas, is a new kind of accelerometer. Accelerometers work in the environment with a wide range of temperature, which can result in poor stability of them. Since most parts of the accelerometer are connected together using adhesive, its accuracy is directly affected by the adhesive's properties and the assembly errors caused by dispensing inaccuracies. Moreover, the pendulum component is assembled by multiple parts, and the mismatch of different materials' parameters can also have an impact on the accuracy of the accelerometer. In this subject, the assembly factors of the pendulum component were studied based on the analysis of the accelerometer bias error.By studying the operational principle and the structural features of the photoelectric accelerometer, a system block diagram and a mathematical model of the accelerometer were established. With the analysis of pendulosity KB, disturbance torque AM and luminous flux error ??, it was found that the static bias of the accelerometer was influenced by the curing temperature of the adhesive and the pendulum component assembly error caused by dispensing. The temperature stability formula of bias was derived. The main factors influencing the temperature hysteresis loops were the temperature change speed and the mismatch of the parameters of materials of the pendulum components parts.Most parts of the photoelectric accelerometer are assembled by adhesive, and the adhesive does not have bond strength until the curing is completed. By analyzing the curing process of the epoxy resin adhesive, the curing temperature was determined. Finite-Element-Method was used to analyze the relationship between curing temperature of the layer and the static bias of accelerometer. The higher the curing temperature, the greater the layer thermal stress, and the thermal stress determined the value of the static bias. In this case, measures were proposed to reduce the bias based on the conclusion. Three assemble errors that caused by the failure of controlling of the adhesive's amount and position were studied, and with the analysis of the influence of these errors on the static bias of the accelerometer, the articular surface coplanar error of the flexible rod was found to be the most affective factor of the static bias. According to the conclusion and the production process, a new assemble accuracy was proposed.Environment temperature changes will cause the bias change of the accelerometer, which will result in the inaccuracy of the accelerometer's compensation. This paper established the temperature conductivity model of the photoelectric accelerometer. The thermal-structural coupling module in ANSYS was used to analyze the influence of the temperature change rate on the temperature hysteresis loops. In this way, the minimum time, which was taken by the outside temperature change to be fully transferred to the internal accelerometer, was determined, and measurements that could reduce the impact of the outside temperature on the accelerometer were proposed. Single factor variable control method was used to research the influence of the mismatch of the three materials' parameters. Through comparative analysis, the decreasing order of the influence' s degree was:the mismatch of thermal expansion coefficient a, specific heat capacity cp, thermal conductivity ? and density ?, which provided the condition to reduce the temperature hysteresis loops.