基于闭环灵敏度的微加速度计制造误差的评估

Assessment for Fabrication Errors of Micro-accelerometers Based on Closed-loop Sensitivity

微加速度计的制造误差对灵敏度、量程、线性度等指标均有重要影响,文中基于电测法和微加速度计的闭环灵敏度,提出了一种简便且准确的评估制造误差的方法。文中首先基于有限元法提取了梳齿电容与质量块位移之间的函数关系。其次,基于电容-位移函数以及闭环微加速度计必须满足的平衡条件,推导出了灵敏度的计算公式。最后,基于灵敏度公式与实测灵敏度值,反推得到微加速度计的制造误差。文中以两种不同几何尺寸的微加速度计为例,通过实验验证了文中所提出方法的正确性。

Fabrication errors of micro-accelerometers have significant impacts on the sensitivity,measuring range and linearity of micro-accelerometers.Based on electrical measuring method and closed-loop sensitivity of micro-accelerometers,a convenient and precise method to assess the fabrication errors was proposed in this paper.The functional relationship between the displacement of proof-mass and comb-capacitance was obtained based on finite element method.Furthermore,based on the capacitance-displacement functional relationship and static equilibrium equation that closed-loop micro-accelerometers satisfies,the formula of sensitivity is derived.Finally,based on the sensitivity formula and measured values of sensitivity,fabrication errors of micro-accelerometers were obtained.Two kinds of micro-accelerometers with different designing sizes were taken as examples to demonstrate the correctness of the method proposed in this paper.