集装箱用电容式加速度传感器的热变形分析

Thermal Deformation Analysis of Capacitive Accelerometer for Container

热变形是导致加速度传感器输出特性随温度变化的主要原因。在分析电容式加速度传感器工作原理的基础上,采用有限元方法对加速度传感器的热变形进行了仿真分析。仿真结果表明:当传感器结构完全对称时,差分方式将结构的热变形相互抵消,传感器的输出不会发生变化;加工误差导致的结构不对称使变热形向刚度较小的一侧发展,从而使传感器的输出产生漂移。温漂试验表明,当环境温度升高40℃时,传感器的输出下降了76 mV。加工中应严格控制工艺流程,确保传感器结构对称,减小热变形。

Thermal deformation is the main reason for the change of accelerometer output with the temperature. Based on analysis of the working principle of capacitive aceelerometer, finite element method was applied in the simulation of thermal deformation. Calculation results indicated that when the sensor structure is symmetrical completely, the differ- ential configuration can cancel the thermal deformation and there is no drift for the output of accelerometer; when nonsymmetry occurs by machine error, the thermal deformation will develops towards the direction of less strength, and the temperature drift occurs. The temperature drift experiment indicated that when temperature increasing 40 ℃, the output of accelerometer decreases 76 mV. It was suggested that capacitive accelerometer should be manufactured accurately to reduce thermal deformation of sensor structure.