在这项研究中,分析了基于静电刚度的微机械谐振加速度计的动力学方程,得到了影响灵敏度的参数。可以通过增加检测检测质量和面对检测电容器板的面积以及通过减小折叠梁的刚度和板电容器之间的初始距离来增加灵敏度。灵敏度也与检测电压有关:检测电压越大,灵敏度越大。建立了加速度计闭环自激驱动的动力学方程,用平均周期法得到了振动振幅的稳态平衡点和稳定条件。在PI控制器的约束条件下,当加载加速度变化时,振动幅度与参考电压和接口电路的预转换系数有关,与品质因数无关。当加载电压为2V时,灵敏度为321Hz/g。使用三种Allan方差分析方法,在室温下30分钟内获得了0.04Hz的频率偏差和0.06mV的幅度偏差。当培养箱中的温度误差为±0.01°C时,频率偏差减小到0.02Hz,分辨率为56ug。完全重叠的Allan方差分析方法(FOAV)需要大量数据,并且需要很长时间才能实现,但具有三种方法中最准确的稳定性。
In this study, a dynamic equation for a micromechanical resonant accelerometer based on electrostatic stiffness is analyzed, and the parameters influencing sensitivity are obtained. The sensitivity can be increased by increasing the detection proof mass and the area facing the detection capacitor plate and by decreasing the stiffness of the fold beams and the initial distance between the plate capacitors. Sensitivity is also related to the detection voltage: the larger the detection voltage, the greater the sensitivity. The dynamic equation of the closed-loop self-excited drive of the accelerometer is established, and the steady-state equilibrium point of the vibration amplitude and the stability condition are obtained using the average period method. Under the constraint conditions of the PI controller, when the loading acceleration changes, the vibration amplitude is related to the reference voltage and the pre-conversion coefficient of the interface circuit and has nothing to do with the quality factor. When the loading voltage is 2 V, the sensitivity is 321 Hz/g. Three Allan variance analysis methods are used to obtain the frequency deviation of 0.04 Hz and the amplitude deviation of 0.06 mVwithin 30 min at room temperature. When the temperature error in the incubator is ±0.01 °C, the frequency deviation decreases to 0.02 Hz, and the resolution is 56ug. The fully overlapping Allan variance analysis method (FOAV) requires a large amount of data and takes a long time to implement but has the most accurate stabilityof the three methods.