Structure-air damping coupling analysis of micromachined gyroscope

This paper presents a method to calculate the air damping coefficient and the quality factor value in MEMS gyroscope at different cavity pressures. Taking the structure of MEMS gyroscope as an example, firstly, the authors derived the simplified M-C-K dynamic model. Then, the elements of mass matrix and stiffness matrix were calculated based on certain assumptions, especially the air damping coefficient with the theory of slide-film damping and squeeze-film damping. Finally, with relative elements of mass, damping and stiffness matrix, we obtained the quality factors Qs in the driving direction and the sensing direction at different cavity pressures. The results showed that the quality factors Qs both in the driving direction and the sensing direction increase with the decrease of the cavity pressure, and the quality factor Q in the driving direction is much bigger than that in the sensing direction.