The Research Of The Free-drive Tri-axial MEMS Gyroscope Used In Spinning Projectiles

Because the installation space of conventional missile is limited and the environment ofconventional missile is harsh such as high impact, high dynamic, high rotation in the launchand flight, the free-drive tri-axial MEMS gyroscope is presented in this paper. The gyroscopedrove by the high spin of the conventional missile to measure pitching and yawing, thereforee the design of the gyro-driven structure and drive circuit is eliminated. Through the analysisand resolving of the output signals of gyroscope, rolling, pitching and yawing was extracted,the there-axis angular rate measurement is realized in single chip.In this paper the main content and results are as follows:1. The mathematical model of the gyroscope was established. Through the detailedintroduction of the work principle of the gyroscope, the dynamic model of the gyroscope wasestablished according to the work principle, and through the analysis of the model, the outputsignal model of the gyroscope was established.2. The structure of the gyroscope was designed. Based on the analysis of dynamic parametersof the model, by making the inherent frequency, mass amplitude, the quality of resistance tooverload ability of gyroscope measure structure to achieve optimal, and designs the parts ofgyroscope combined with MEMS processing technology. Finally, stimulates the inherentfrequency, mass amplitude, the quality of resistance to overload ability of the structure withANSYS software.3. The fabrication process of the structure of gyroscope was designed. Based on the detaileddescription of the MEMS silicon micro-machining process, combine with the characteristicsof the structure, the process layout and production process of the gyroscope was designed.4. The detect circuit of the weak signals of the gyroscope was designed and produced. Firstly,the measure methods of the weak capacitance was researched, the bridge type circuit methodwas chose to measure the gyroscope’s output signals by comparing the advantages and disadvantages of various measurement methods. Secondly, based on the characteristics ofbridge circuit and the variation of the gyroscope micro capacitance, the gyroscope’s signalsdetect circuit was designed. Finally, the circuit was tested.5. The calculating program of the gyroscope’s three-axis angular rate was design and verified.Firstly, the extract method of the gyroscope’s three-axis rate was designed based on theanalysis of the gyroscope’s output signals. Secondly, the calculation of the phase difference inthe extraction program and solution method of pitch and yaw angle rate was highlights.Finally, the extract method was verified in experiment.