Eigenmode operation of piezoelectric resonant gyroscopes  

作　　者：Mojtaba Hodjat-Shamami Farrokh Ayazi 

机构地区：[1]School of Electrical and Computer Engineering,Georgia Institute of Technology,Atlanta,GA 30308,USA

出　　处：《Microsystems & Nanoengineering》2020年第1期95-105,共11页微系统与纳米工程（英文）

基　　金：This work was supported in part by the DARPA Microsystems Technology Office Single-Chip Timing and Inertial Measurement Unit(TIMU)program through SSC Pacific contract#N66001-11-C-4176。

摘　　要：The theory of eigenmode operation of Coriolis vibratory gyroscopes and its implementation on a thin-film piezoelectric gyroscope is presented.It is shown analytically that the modal alignment of resonant gyroscopes can be achieved by applying a rotation transformation to the actuation and sensing directions regardless of the transduction mechanism.This technique is especially suitable for mode matching of piezoelectric gyroscopes,obviating the need for narrow capacitive gaps or DC polarization voltages.It can also be applied for mode matching of devices that require sophisticated electrode arrangements for modal alignment,such as electrostatic pitch and roll gyroscopes with slanted electrodes utilized for out-of-plane quadrature cancellation.Gyroscopic operation of a 3.15MHz AlN-on-Si annulus resonator that utilizes a pair of high-Q degenerate in-plane vibration modes is demonstrated.Modal alignment of the piezoelectric gyroscope is accomplished through virtual alignment of the excitation and readout electrodes to the natural direction of vibration mode shapes in the presence of fabrication nonidealities.Controlled displacement feedback of the gyroscope drive signal is implemented to achieve frequency matching of the two gyroscopic modes.The piezoelectric gyroscope shows a mode-matched operation bandwidth of~250Hz,which is one of the largest open-loop bandwidth values reported for a mode-matched MEMS gyroscope,a small motional resistance of~1300Ω owing to efficient piezoelectric transduction,and a scale factor of 1.57nA/°/s for operation at atmospheric pressure,which greatly relaxes packaging requirements.Eigenmode operation results in an~35dB reduction in the quadrature error at the resonance frequency.The measured angle random walk of the device is 0.86°/√h with a bias instability of 125°/h limited by the excess noise of the discrete electronics.

关 键 词：POLARIZATION PIEZOELECTRIC MODE 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置] TH824.3[自动化与计算机技术—控制科学与工程]