电容式z轴微机械陀螺的噪声抑制

将z轴微机械陀螺两个模态的机械噪声效应等效为各自在单位噪声力作用下的振动,根据陀螺的工作原理得到两个噪声力作用下陀螺敏感模态的机械输出噪声。建立了包含运放和电路板非理想因素在内的接口电路的噪声模型。结合机械噪声模型和接口电路模型噪声,建立了包括结构参数和电路最小检测电容量在内的陀螺的噪声等效输入角速度模型,为陀螺的设计优化提供了参考。分析了结构参数对陀螺等效输入角速度噪声影响,并采用两个参数不同的电容式z轴微机械陀螺进行了实验。结果表明,通过结构参数的调整,将电容式z轴微机械陀螺的输出噪声从414μV/Hz降低至235μV/Hz。

Noise Reduction of Capacitive z-Axis Microgyroscopes

The mechanical noise effects of the two oscillation modes of the microgyrscope were presented as act of two unit forces to it.Based on the working principle of microgyrscopes,the mechanical output noises of the sensitive mode were obtained.Considering the non-ideal factors of amplifier and the printed circuit board,an interface circuit electronic noise model was built.Combining the total noise model of z-axis microgyroscope including the mechanical and electronic noises,the structure parameters and the minimum detective capacitor were used to represente the equivalent noise input,which provides the reference of the optimum design of the z-axis microgyrscopes.The influence of the structure parameters on the equivalent noise input was analyzed.The experiments based on two different capacitive z-axis microgyroscopes were carried out,and the results prove that the output noise can be decreased from 414 μV/Hz to 235 μV/Hz by changing the structure parameters.