A High Q-Factor Outer-Frame-Anchor Gyroscope Operating at First Resonant Mode.

Bo Jiang,Fumin Liu,Guowen Liu,Yan Su,Lemin Zhang

doi:10.3390/mi11121071

Abstract

Disc gyroscope manufactured through microelectromechanical systems (MEMS) fabrication processes becomes one of the most critical solutions for achieving high performance. Some reported novel disc constructions acquire good performance in bias instability, scale factor nonlinearity, etc. However, antivibration characteristics are also important for the devices, especially in engineering applications. For multi-ring structures with central anchors, the out-of-plane motions are in the first few modes, easily excited within the vibration environment. The paper presents a multi-ring gyro with good dynamic characteristics, operating at the first resonant mode. The design helps obtain better static performance and antivibration characteristics with anchor points outside of the multi-ring resonator. According to harmonic experiments, the nearest interference mode is located at 30,311 Hz, whose frequency difference is 72.8% far away from working modes. The structures were fabricated with silicon on insulator (SOI) processes and wafer-level vacuum packaging, where the asymmetry is 780 ppm as the frequency splits. The gyro also obtains a high Q-factor. The measured value at 0.15 Pa was 162 k, which makes the structure have sizeable mechanical sensitivity and low noise.

Highlights

The mechanical vibratory gyroscope has made significant progress using micromechanical technology
Disc resonator gyros (DRG) is an in-plane resonator, and it is complemented through silicon-based microelectromechanical systems (MEMS) fabrications
The advantages meet the requirements of low-cost, small volume, and high performance [6]

Summary

Introduction

The mechanical vibratory gyroscope has made significant progress using micromechanical technology. It owns a similar kinetic theory with Hemispherical Resonator Gyroscope (HRG), developed initially for aircraft navigation. UC Davis and Stanford University research groups reported that a multi-ring device with epitaxial silicon has a Q factor of 80 k and a resonant frequency of 250 kHz [8,9]. The situation is different for high-frequency resonators (e.g., more than 1 MHz), such as the solid disc with nanometer-level gaps [15]. Gas damping is another critical source of energy loss practically. The paper illustrated the relationship between bias voltage and the resonant frequency of two degenerated modes. The quality factors at different ambient pressure reveal that the structural damping dominates when air pressure is below 0.3 Pa for the structure

Kinetic Equations and Error Analysis

Multi-Rings Structures with Low Thermoelastic Damping

Discussion

Conclusions