微机械陀螺非线性特性的自由衰减振荡测量方法

Free damped oscillation measurement method for the nonlinear features of micromechanical gyroscopes

针对微机械陀螺非线性特性的测量问题,研究了一种频率步进式正弦脉冲激励的自由衰减振荡测量方法。在谐振频率附近,采用步进式正弦脉冲序列作为激励信号,得到一组包含系统不同程度非线性动力学特征的自由振动响应信号。通过Hilbert变换提取自由振动信号的瞬时幅值和瞬时频率,计算得到骨架曲线簇,即可实现非线性动力学特性的实验测量。以Duffing系统为例,对不同信噪比自由振动响应信号进行了数值仿真,结果表明这种方法比FREEVIB方法具有更好的抗噪声性能。对一种环型振动微陀螺进行了实验测试,所得到的骨架曲线与传统扫频方式的测量结果一致。作为一种测试手段,这种方法同样可用于其他类型微机械谐振器动力学特性的实验测试。

In order to measure the nonlinear features of micromechanical gyroscopes,a free damped oscillation measurement method based on stair-stepped frequency sinusoidal pulses excitation is investigated. In the vicinity of the resonant frequency,a frequency stepped sinusoidal pulse sequence is employed as the excitation signal. A set of free vibration response signals containing different degrees of system nonlinear dynamical characteristics are obtained. The Hilbert transform is used to extract the instantaneous amplitudes and instantaneous frequencies of the free vibration signals,a cluster of backbone curves is calculated,and therefore the experiment measurement of the nonlinear dynamic characteristics can be implemented. Taking Duffing system as an example,the numerical simulations for the free vibration response signals with different signal-to-noise ratios（ SNRs） were carried out. The results show that the proposed method has better anti-noise performance than FREEVIB method. A vibrating ring shape micromechanical gyroscope was tested in experiment. The obtained backbone curves are consistent with the measurement results obtained using traditional frequency sweeping method. As a test method,the proposed technique can also be used in the experiment test of the dynamic characteristics of other types of micromechanical resonators.