Design of A Completely Decoupled 3-Degree-of-Freedom Micromachined Vibratory Gyroscope

Abstract

This paper presents a novel 3-degree-of-freedom (DOF) micromachined vibratory gyroscope with completely decoupled structural design. A single-DOF drive mode and a complete 2-DOF vibratory structure, including proof mass, proof frame and detection mass, are applied in designed structure. The drive mode and sense mode are linked by proof mass and proof frame, which also isolate driving element (driving frame) and sensing element(detection mass) to achieve structural decouple. Meanwhile, the 2-DOF sense mode could provide a flat region between two resonant frequencies, which improves the robustness of micromachined vibratory gyroscope. The finite element analysis(FEA) illustrated the resonant frequency of drive mode is between two resonant frequencies of sense mode, showing the feasibility of the proposed gyroscope structure. The simulation results demonstrated a 3-dB bandwidth of 400Hz from 4.8 kHz to 5.2 kHz in sense mode, which improves the inherent robustness to structural parameters and environmental variations. In addition, the structure decoupling is verified through the simulation and the driving elements and sensing elements are immune to vibration of sense mode and drive mode respectively.