Design and Fabrication of MEMS Decoupled Gyroscopes with Wide Operation Bandwidths and High Detection Sensitivity
Date Issued
2009
Date
2009
Author(s)
Shen, Ching-kai
Abstract
Due to the progresses of the automation and the navigation technology, applying MEMS manufacturing process to produce miniaturized vibratory gyroscope begins the development of novel gyroscopes with the requirement of small volume, low prices, and high compatibility to systems. There are many applications in commercial electronic commodities and many breakthroughs in academic studies by the positioning function of gyroscopes.he main mechanism of the vibratory MEMS gyroscopes is that when rotation occurs, the Coriolis force which is vertical to the driving vibratory direction makes the sensing mass vibrate. Thus, we can detect the angular velocity by reading the output signal from sense. We adapt the concept of the decoupled structures for raising sensitivity. In addition, the matching between drive and sense, and the quality factor (Q) are both important considerations.he target of this study is to increase the bandwidths of the frequency responses of drive and/or sense to improve the sensitivity of the designed devices without sacrificing Q factors. Two kinds of designs of MEMS gyroscopes with decoupled structures will be presented in this thesis. The first is circularly vibratory structure which has four different-weighted masses to equivalently increase the bandwidth of driving frequency response. The second is perpendicularly vibratory structures which, with gradually increasing frequency, make the spectrums of adjacent vibration modes of drive or sense be broadened via the coupling of micro-mechanical elastic beam.e use simulation software to analyze the natural resonant frequencies and the dynamic responses of these two kinds of structures, and then observe the resultant diagrams to verify the bandwidths enlargement function. Through the initial experiments of the resonant frequency of L-shape’s vibratory mass, the consequences can correspond to the simulation results. It is proved that the designed devices indeed have the bandwidth-magnified effect, and lead to the rise of matching between drive and sense. Therefore, the goal is initially achieved!
Subjects
MEMS gyroscope
resonant frequency
decoupled structure
circularly vibratory structure
reciprocally vibratory structure
frequency response
Type
thesis
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