Fence Structure Micromachining Vibratory Rate Gyroscope

This thesis describes the investigations on the design, fabrication and characteristics of a novel micromachined vibratory rate gyroscope, which can work at atmospheric pressure.By means of the theoretical analysis of the dynamic characteristic of micromachined vibratory rate gyroscope, we get following conclusion: The micromachined vibratory rate gyroscope will have high sensitivity and wide bandwidth at the same time when the natural frequencies of the driving mode and sensing mode have a departure, meanwhile the damping of driving mode and sensing mode are as far as possible identical and as far as possible little.We proposed a novel micromachined vibratory gyroscope with fence structure. The electrostatic analysis of the gyroscope with fence structure shows that the drives with fence structure can be used to drive and sense motion of the proof mass in the plane of the devices. And the normal electrostatic force of fence structural capacitor can be neglected for the influence of the device property.The air damping analysis of the fence structural micromachined vibratory rate gyroscope shows that the air damping in the driving mode and the sensing mode of the device is slide film damping mainly, therefore the coefficient of damping force is comparatively little, and the quality factor of both them is close to.From the theoretical analysis of the gyro, we proposed the equivalent electrical model of the fence structural micromachined vibratory rate gyroscope. The driving-circuit and the detecting-circuit were designed. In PSpice, we simulated the detecting-circuit using the equivalent model of the gyro at behavior level, verified the function of the detecting-circuit, and determined the parameters of circuit modulars.feasible. The establishment of the equivalent electrical model of the fence structural micromachined vibratory rate gyroscope brings convenience for the optimization designs of the gyro detection circuit in the future.The fence structural micromachined vibratory rate gyroscope was designed and fabricated. The characteristic test systems of the gyro were set up. The various resonant modes, characterization of the rotation rate response of the gyroscope and the mechanical couple property were detected using these test systems. The test results show that the scale factor, nonlinear difference and angular rate scale rang of the fence structural micromachined vibratory rate gyroscope are 20 mV /s ?/ s ,0.56%, and ?300 ?/ s respectively at atmospheric pressure. Device property test results show that the fence structural micromachined vibratory rate gyroscope works at atmosphere is feasible. Since the gyro has near and higher quality factor of driving mode and sensing mode, the gyroscope can have the higher sensitivity and wider bandwidth at atmosphere.