Abstract
This thesis presents the structural design of a single-axis MEMS vibratory gyroscope, which combines the fully-decoupled mechanism with the tuning fork architecture (a FDTF gyro), to enhance the gyroscope performances. The fully-decoupled mechanism is realized by introducing the Coriolis-mass between the drive system and the sense system, and utilizing the orthogonally arranged 1-DOF (degree of freedom) springs as the interconnections. Therefore, the motions of the operating modes of the FDTF gyro are independent, resulting in a low coupling (quadrature) error. Moreover, the FDTF gyro consists of two fully-decoupled systems, which are connected to each other through the specific coupler designs to form the tuning fork architecture. As the result, the FDTF gyro enables the anti-phase drive and sense operations, and enhances the vibration resistance utilizing the T-shaped lever coupler design and the differential sensing scheme. This thesis introduces the operating principles and error sources of the MEMS CVGs, and the detailed measurement setup and results are also be given and discussed. Experimental results show the fabricated FDTF gyro has a small quadrature error of 100 deg/s, and the acceleration sensitivity is below 0.5 deg/s/g, showing the feasibility of the proposed structural design. Moreover, the stability and long-tern operation characterizations are also examined. The non-linearity is 0.6 % (within 300 deg/s) and the scale factor variation w.r.t. temperature is 0.3 %/K. The bias instability of the FDTF gyro is 0.8 deg/hr and the ARW is 3 deg/hr/sqrt(Hz), satisfying the Tactical-grade requirements.