Research On Design & Manufacture Of Sensitive Element Of Micromachined Quartz Gyroscope

MEMS is rising new technology in recent years which has a bright future. MEMS promotes micro inertial technology in various applications of inertial field. Micro inertial technology includes micromachined accelerometers and micromachined gyroscopes, etc. Micromachined quartz gyroscope has developed faster than others in micromachined gyroscopes. Micromachined quartz gyroscope is one type micromachined inertial sensor, emerged in 1980s, which is classified to rate grade. Due to its lower cost, small volume, simple structure, high reliability, etc., micromachined quartz gyroscope has promising applications, such as military rate grade devices and non-military civil automobiles.This dissertation placed emphasis on some issues of micromachined quartz gyroscope, based on review of present developments and research of micromachined quartz gyroscope at home and abroad. Design, manufacturing and vibrating testing of micromachined quartz gyroscope presented in this dissertation were summarized asfollows:Material characteristics of quartz crystal and dynamic problems of micromachined quartz gyroscope have been summarized and studied. This dissertation proposes that torsion which has been produced by Coriolis moment is a key to realize machine decoupling of micromachined quartz gyroscope. The axiomatic design mode of the mechanical structure of Coriolis vibratory gyroscope is proposed, based on fundamental study of axiomatic design theory and operating principles of Coriolis vibratory gyroscope. The axiomatic design mode of vibratory gyroscope which resolved coupling problem of gyroscope design, provides scientific rule for micromachined quartz gyroscope design which is based on the experience, even the intuition. The axiomatic design mode has better instruction significance to standardized design and innovation of micromachined vibratory gyroscope.Based on the axiomatic design mode and investigation of material characteristics of quartz crystal & structure of micromachined quartz gyroscope, a micromachined comb quartz gyroscope is proposed in this dissertation. Its vibratory mode has been investigated by finite element analysis (FEA). Meanwhile, the impact of geometry size on vibrating mode has been revealed. Lumping parameter model of micromachined comb quartz gyroscope is established, therefore, quantitative investigation of drive mode and sense mode is conducted.Driving circuit and detected circuit constitute Micromachined comb quartz gyroscope circuit. Voltage rising is achieved using ADM8660. Sine drive signal with constant frequency & coequal amplitude of vibration is obtained using special signal XR-2206. Magnification, demodulation & filting of out signal of gyroscope are carried out by detected circuit. Using charging amplifier and locking amplifier,the signal of high signal-to-noise can be gained. At last, simulation of detected circuit is performed using MATLAB. According to the simulative result, using locking amplifier,high rate of signal-to-noise can be gained as long as deal with noise and filting of circuit. Some manufacturing problems of micromachined quartz gyroscope are studied.Combining present conditions, this dissertation discusses ultrasonic manufacture and manufacturing mechanisms of quartz. Finally, structure of micromachined comb quartz gyroscope is obtained by using the method of ultrasonic manufacture.In terms of structural features of MEMS with small size & ultra high frequency, multi-loading device uesd for MEMS is fabricated. Through multi-loading device,static & dynamic testing of MEMS can be performed in vacuum. Precise control of base excitation, temperature and pressure can be achieved. At the same time, according to the mentioned advantage points, vibrating modal investigation of micromachined comb quartz gyroscope is carried out.