微机械陀螺品质因数的在线测量方法

品质因数是决定微机械陀螺结构性能的重要参数。传统测量振动结构品质因数的幅频曲线半功率带宽法需要记录大量幅频响应数据并需作离线处理,测量效率很低。通过分析微机械陀螺动力学模型发现,品质因数可根据谐振频率及相频函数在谐振频率点处的一阶导数值计算,且相频曲线在谐振频率点附近近似为线性。利用这些特点,提出一种新的品质因数在线快速测量方法。首先,在谐振频率附近对陀螺进行激励,得到相频数据;然后,使用递推最小二乘法估计出相频曲线斜率;最后根据该斜率和谐振频率值计算出品质因数。新方法不需要存储和离线分析频率响应数据,可以自动确定品质因数。仿真和实验验证了本文方法的正确性和可行性。

On-line measurement for the quality factor of the micro-machined gyroscope

Quality factor is a key parameter determining the performance of the micro-machined gyroscope. The conventional measurement using the half-power bandwidth method is low efficiency, since it requires user to store and deal with lots of amplitude-frequency response data. Based on the analyses on the dynamics model, the quality factor can be calculated according to the resonance frequency and first derivation of the phase-frequency function at the resonance frequency point, and the phase-frequency graph is approximately linear near the resonance point. Upon these characteristics, an online and quick quality factor measurement method is put forward in this paper. First, the gyroscope is excited near the resonance point to obtain the phase-frequency data. Then, the slope of the phase frequency is estimated using recursive least squares method. Finally, the quality factor is obtained according to the slope and the resonant frequency. The simulation and experimental results verify the correctness and feasibility of the proposed method.