Planar Foucault pendulum silicon gyro

This paper presents theoretical performances of a novel silicon MEMS Coriolis Vibratory Gyroscope (CVG). Since whole-angle (WA) operation is promising to reach navigation grade, this work proposes an innovative cell design to obtain isotropic in-plane vibration of a central mass, as a Foucault pendulum. This design, based on original link elements between the outer frame and the central mass allows the in plane central mass vibration without energy losses in the outer frame. A FEM calculation shows very low energy losses in the outer frame, of the order of 10-7 of the total energy contained in the resonator. Thus, for a device under vacuum only the thermoelastic losses will limit the Q-factor estimated above 8.5 × 105. We predict with our size design of 2.5 mm × 2.5 mm × 80 µm an angular random walk (ARW) of 0.007 °/√h in close loop configuration. The operating frequency is about 8 kHz and the first eigen mode is above 4.7 kHz, making the device robust to harsh vibratory environments.