Rotation Error Suppression for a Doubly Decoupled MEMS Gyroscope

Abstract

doubly decoupled spring structure has been widely used in MEMS gyroscopes to suppress the cross- coupling between gyroscope driving mode and sensing mode. However, rotation and translation error of the sensing mode limits the performance of doubly decoupled gyroscopes. We propose three ways to further suppress the rotation error. Firstly, by reducing the stiffness of the decoupling beam to reduce the coupling stress and keeping approximately mode matching of gyroscope driving and sensing mode. Secondly, by reducing the effective lever arm length of the decoupling structure by adopting a trapezoid connection design , and thus the overall lever torque and the rotation angle of the sense frame are both lowered. In addition, we propose a novel rotation suppression electrode on the sense frame to further suppress rotation of sensing mass. Finite element analysis results demonstrate that, comparing to the decoupled structure using rectangular connection, the trapezoid connection structure we propose suppresses the rotation error by 71.3%;the rotation error can be further suppressed by our rotation suppression electrode, the suppression level is 14% at 4V applied voltage which can be further improved with increased suppression voltage..