硅微机械陀螺谐振频率在线快速测定方法

Online and quick determination of resonance frequency for silicon micro-machined gyroscope

传统测定硅微机械陀螺谐振频率的扫频法需要记录所有频率输入与幅值响应的值,效率低且实现较为复杂。提出一种在线快速测定方法,根据硅微机械陀螺模态特性,将谐振频率的确定视为寻找幅频函数在定区间上的极大点问题,然后利用黄金分割搜索法求解该极大值点。仿真显示,在信噪比为50 dB的噪声水平下,仅需少量的样本点即可收敛到真值附近,测量相对误差在10-6量级上。基于FPGA实现了嵌入式测试系统,分别采用传统扫频法和本文方法进行测量,二者得到的结果相近(相对误差在10-6量级上),从而验证了方法的有效性。

Traditional frequency sweep method for measuring resonance frequency is poor efficiency and difficult to implement because it requires storing all the frequencies of input signal and the amplitudes of responding signal.In this paper,an online and quick method is put forward.According to model characteristic of silicon micro-machined gyroscope,the measurement of resonance frequency is regarded as the determination of maximum of amplitude-frequency function in a fixed range.The golden section search technique is applied to find the maximum point.Simulation shows that the measurement results converge quickly and the relative error is less than 10-6 when SNR in sampling is about 50 dB.An embedded testing system based on FPGA is implemented,and the measurement results by the proposed method are close to that by the frequency sweep method（the relative error is at the level of 10-6）,which validates the proposed method.