力平衡式真空微电子加速度传感器的机电耦合特性(英文)

Electromechanical coupling characteristics for force-balanced vacuum microelectronic accelerometer

力平衡式真空微电子加速度传感器的惯性敏感元件不仅受弹性力的作用,同时还受静电力的作用,其总刚度为机械刚度和由静电力引入的电学刚度之和。本文利用平行板电容器模型计算发射电极间的静电力,并引入一个修正系数描述发射锥尖阵列的影响,对传感器性能进行了理论分析。分析表明,提高偏置电压可以改善传感器的线性度和灵敏度,通过调节偏置电压来调整系统的刚度和阻尼比可使其具有更好的动态特性。由于静电吸合效应的影响,质量块的位移必须小于偏置电极间初始间距的1/3 ,系统才能稳定。为了获得较好的动态特性,需要确定一个由偏置电压决定的优化工作点。实验结果表明,当设置发射电压和反馈偏置电压分别为1.953 V和5.478V时,该真空加速度传感器的灵敏度达到557mV/g,非线性度为0.95%,传感器系统具有良好的性能。

The inertia sensitive component of a force balanced vacuum microelectronic accelerometer is effected by both the elastic force and the electrostatic force,and its total stiffness is the sum of the me chanical stiffness of the beams and the equivalent stiffness produced by the electrostatic force. In con siderasion of the effect of emitting tip array, this paper introduces a revised constant a greater than 1 to compute the actual electrostatic force by using the model of a parallel plate capacitor. The analysis shows that the linearity and sensitivity of the vacuum microelectronic accelerometer has been improved by increasing preload deflection voltages, so the stiffness and damping ratio of the system can be adpull-in, the displacement of proof mass must be less than one-third of the original distance between two deflection electrodes. Moreover, in order to obtain good dynamic characteristics, an optimum working point determined by the preload deflection voltage must be set. The experimental results show that the nonlinearity and sensitivity of the accelerometer are 0.95% and 557 mV/g when the deflection voltage and the emission voltage are 5. 478 V and 1. 953 V, respectively, which indicates that the sensor has good performance.