Design And Analysis Of A Micromachined Vibrating Gyroscope

This thesis describes the investigations on the design and characteristics of a novel de-coupled micromachined vibratory rate gyroscope, which can work at atmospheric pressure.1. By means of the theoretical analysis of the micromachined vibratory rate gyroscope, we get following conclusions: The microgyroscope can be driven by tangent electrostatic force produced by fence structure electrodes,and the normal electrostatic force can be neglected for the influence of the device property; The parasitical capacitance and fringing effect can't be neglected for the calculating of the detection capacitance; The coefficient of damping force is comparatively little when the air damping in the driving mode and the sensing mode of the device is the Couette flow damping.2. The mechanical coupling error between drive mode and detection mode is analyzed, and the analysis shows that the quadrature error have a big influence on detecting precision.3. A micromachined vibratory rate gyroscope which can work at atmospheric pressure is presented in this paper,but a main problem of which was discovered through FEA analysis: the mechanical coupling error can easily arise if the mass and the supporting beams are not completely symmetrical as a result of fabrication error during silicon micromaching.4. A novel three spring-mass structure is designed to close off the cross-axis coupling, the simplified dynamics model of which is worked out. According to this structure, a de-coupled microgyroscope is designed, and the simulation results indicated that this three spring-mass structure can effectively eliminate the coupling effects between the drive and sense mode. It is expected that the applications of the structure can make it easier to design detecting-circuit of microgyroscope and minish the requirement of manufacture precision.5. The equivalent electrical model of the de-coupled micromachined gyroscope is worked out,and the fabrication process and the problems maybe appear are discussed initially for the future work.