Study On Key Technologies Of Silicon Microgyroscopes For Improving Performance

Along with the research and rapid development of Micro-ElectroMechancial Systmes(MEMS), and the present demand for low-cost, small and reliable angular rate sensors, silicon micromachined gyroscopes have become a major focus of wide research and development in the past decades. The silicon micromachined gyroscopes are on the way to becoming a mass product for a variety of applications within the coming years.At present, the silicon micromachined gyroscopes are used in field needed middle and low precision. It's urgent to improve the performance of gyroscopes for the need of high precision gyroscopes. The relative error of machining is large, which has large affection on the performance of gyroscopes. It's important to reasonable design structure of gyroscopes. In order to improve performance of gyroscopes, the quadrature error and stray capacitance of electormechannical interface are studied in this thesis, and the details are as follows:1)The theoretical analysis of quadrature errorThe quadrature error is induced by theoretical error and machining error. Based on the dynamic equations of silicon micromachined gyroscope, the theoretical qudrature error was analyzed. The qudrature error arising from machining error is analyzed in detail by using the theory of stiffness matrix. The results show that the quadrature error resulted from machining error is much larger than that induced by theoretical error. Conclude that the cross-axis coupling coefficients of stiffness between drive and sense direction should be as small as possible to reduce the quadrature error.2)The design principle of suspension beamsEnergy methods are used to obtain the stiffness of folded-flexure suspension, and whose design principle is put forward. The stiffness of crab-leg-spring, U-spring and serpentine spring are listed in this paper, and the rules of stiffness are concluded .The design principle of suspension beams for silicon micromachined gyroscopes is brought forward to decrease the quadrature error.3)Analysis of the electromechanical interface modelAccording to the plate of gyroscope, the model of electromechanical interface is built. Capacitance and resistance are theoretically analyzed, and the relationships among capacitance, resistance and useful signals have been achieved. At last, the design principle of disposal wires is put forward according to the results of analysis.4)improvement of z-axis silicon miceomachined gyroscopeThe dynamic equations with machining error were derived based on the mechanical model of z-axis silicon micromachined gyroscope(SZG1). The equations of quadrature displacement are derived with machining error, and the relationship among quadrature error, stiffness and quality factor is derived. The structural form and parameters of folded-flexure suspension are optimized, and the design principle of transverse suspension is put forward. The wires are disposed symmetrically and new...