Analysis and compensation of mass imperfection effects on 3-D sensitive structure of bell-shaped vibratory gyro

The bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a novel type of solid-state vibratory gyroscope (SVG), which has a three-dimensional sensitive structure as its resonator. Strict symmetry of the 3-D sensitive structure is the key factor to ensure the gyro performance. However, mass imperfection always exists in a physical structure. The aim of this study is to investigate the influence of mass imperfection on gyro performance by analyzing the vibration of standing wave in imperfect resonator, as well as methods to eliminate the influence. Two important influence factors of frequency split and vibration mode offset caused by mass imperfection and the resulting gyro error are analyzed by building the imperfect ring model. The vibration process of imperfect BVG resonator and the quantitative relationship between mass deviation and the two factors above are studied using FEM simulation. Finally, a practical balance method for BVG based on addition of mass is proposed and validated by specific engineering experiments. The results demonstrate that the method is both feasible and easy to implement. Conclusions of this study will contribute to theoretical research and practical development work of BVG.