Dynamic Performance Analysis And Robust Design Of A Tuning Fork Vibratory Micromachined Gyroscope Structure

At present, with ceaseless improvement of micro-electro-mechanical technology (MEMT), development of the technology of the micro-electro-mechanical system (MEMS) tends to be directed forward its application in industrial branches.Especially, design and analysis of microstructure are one of the key technical projects. The demands of not only complexity and environmental applicability of MEMS, but also those of the measuring accuracy, the responding velocity and stability of microsensors are higher and higher.Therefore, the research on the analysis of the dynamic performance based on the substructuring method has a great significance in the improvement of MEMS technology and is necessary to its further development.This paper aims to improve the stability of the dynamic performance from the viewpoint of the demand of the special performance of microstructure.For this, a silicon bulk micromachined tuning fork vibratory gyroscope has been taken as the research object of this paper, and the method for analysis of the dynamic performance of the microstructure has been described in detail.Based on understanding the basic principle of the microstructure and several methods for analysis of the dynamic performance of the microstructure, this paper has suggested the introduction of the analysis method for dynamic performance of microstructure based on substructure method into the research for resolving some problems encountered in the analysis of the performances of microstructures, e.g. improvement of the accuracy and shortening of the calculating time.This paper has also discussed the analyses of the dynamic mechanical model of the micromachined gyroscope, air damp characteristic and the design of the elastic bar; especially, the dynamic substructure method has been applied to analysis for the dynamic performance of the microstructure and the analysis method for the microstructures with great degrees of freedom and complexity has been realized.2. In this paper, the vibration modes for the driving and measuring block of the microstructure, frequency response and real time characteristics have been analyzed by using analysis method for dynamic performance of the substructure.The reasonable vibration modes for the driving and measuring masses have been found and the analyses of the dynamic mechanical characteristics and the measuring properties for the last output performances of the microstructures have been realized.In order to improve the dynamic performances of micromachined gyroscopes, their different elastic-bar structures have been analyzed and the detection capacitance of the micromachined gyroscope has been calculated; the analysis of the dynamic characteristics of the microgyroscope has been carried out; the influence of different mass distributions of the microgyroscope to its performances has been simulated and compared with one another.3. In this paper, the characterization of working environments for multi-physical fields the simulations of the complex dynamic performances have been realized; the analysis method for sensitivity has been studied, which is necessary to evaluate how the single effect and the synergetic effect of the multi-physical fields influence the factors estimating the performances of the microstructureIn order to effectively perform the dynamic optimum design and modification of the microstructure, the influence of the geometrical dimensions and the working temperature to its dynamic performances has been analyzed by the analysis method for the dynamic performances of the microstructure based on the substructure method.Based on the results of the sensitivity calculation, the methodology of the orthogonal experiment optimization has been used to carry out the dynamic optimum design of micromachined gyroscope.4. In order to solve the instability of the performances of products caused by some uncertain factors in the processing techniques, the robust design method for the microstructure based on Taguchi three-stage design has been suggested based on the analysis on the variation of the performance of the micromachined gyroscope caused by processing techniques.Considering the processing errors and the temperature change, Taguchi design method has been used in combination with the dynamic substructure method in the simulation test of the structural parameter to perform the robust design of the micromachined gyroscope.Through the robust design, the optimum design scheme able to realize the minimization of the variance of the system performance under the synergistic influences of temperature variation and key structural parameters ahs been proposed.The microscale dimensions of microstructures can cause uncertain processing errors and difficulties of their performance variations.In this paper, the well-known robust design method has been introduced into determining the key structural parameters in order to ensure the minimum variation of the performance and to improve the stability of the performance from the viewpoint of controlling the qualities and the performances of products.5. In order to characterizing the analysis theory of the dynamic performance of the microstructure and to ensure the accuracy of the theoretical analysis, the experimental research ahs been performed on the tuning fork vibratory micromachined gyroscope; First of all, the frequency responses of the driving and measuring modes of the micromachined gyroscope have been measured; Second, the performance variation of the microgyroscope has been measured in the working temperature range -40℃to 85℃to demonstrate the influence of the working environment of the microgyroscope to its performance.The experiment results have shown that the results of theoretical analysis and measurement are found to be quite consistent with each other and that the numerical simulation and analysis for the dynamic performance of the microgyroscope based on the substructure method can satisfy the demands of the design and the analysis of the microgyroscope and also allow us to find out the optimum parameter values for designs of structure and performance.