Vibration Analysis Of MEMS Micro-gryoscope

As a kind of new inertial sensor, the MEMS micro-gyroscope attracts the extensive attention inenginnering fields. The thesis focused on the vibration analysis of MEMS micro-gyroscope, thecontents of which are as follows.Starting with the analysis of a MEMS micro-gyroscope implementation, the mechanical model ofthe MEMS is presented by using the simpliefied mass-spring-damper systems. It shows that theresonant frequency of gyroscope in drive and sense directions are very sensitive to system parameters.To achieve a stable response, the mechanism of mechanical coupling erros of a siliconmicrogyroscope was studied. For an imperfect machining, the errors caused by the anisoelasticity,asymmetrical damper and the unbalanced mass of the a-axis silicon microscope were analyzed basedon the dynamic equation and matrix theory. The mathematic models of mechanical coupling errorswere put forward, and the numberical results of mechanical doupling errors were given. The resultsshow that the mechanical coupling erros consist of errors in-phase with the useful signals andquadrature errors, in which the quadrature errors are the largest one.After that, a3-DOF micro-machined silicon gyroscope is introduced. The overall gyroscopedynamical system is a total of3-DOF, consisting of a1-DOF drive-mode oscillator and a2-DOFsense-mode oscillator. The frequency response of the sense-direction oscillator has two resonant peaks.Between them there is a flat operating frequency region, where the response gain and phase are bothstable. In order to make the design of micro-machined silicon gyro more practical, the phenomenon ofmechanical-electrical coupling is analyzed. It is found that the real dynamic system includes varies ofnonlinear factors, the stability of the whole system is greatly influenced by the bias voltage and theparameters of capacitance. In order to solve the defects in design, testing capacitances and staticelectricity feedback capacitances are added into so that the drive mode close-loop feedback controlcan be realized. At same time, the output precision of sense mode is improved and the detectionsensitivity of system increased as well.