Research On Several Key Techniques Of Non-driven Silicon Micromechanical Gyroscope

Non-driven structure micromechanical gyroscope is a novel angular rate sensor based on Coriolis force effect, which has not driven part, but utilizes itself circumrotation of the rotating carrier as driven force. It has the characteristics of small size, low cost, simple structure and can sense rolling, pitching and yaw angular rate of the rotating carrier at the same time. The micromechanical gyroscope is a promising sensor, which can be extensively applied to attitude measurement of high-speed-rotating airframe, e.g. rolling airframe missile. So its research has important theoretical significance and practical application value.The dissertation has improved the mathematical model of micromechanical gyroscope, presented the method to compensate the effect of rolling angular rate on the output signal of the gyroscope and achieved the demodulation algorithm of the signal of the gyroscope. According to the above, the paper has designed and implemented the attitude sensor for high-speed-spin vehicle. The main contributions of this dissertation are listed as follows:1. The previous model of micro-mechanical gyroscope fails to consider the existence of both pitching and yaw at the same time. The paper has presented the mathematical model of the micromechanical gyroscope based on Euler equations and the structure characters of the gyroscope. The simulation test has shown that the model is correct. And the theory of the non-driven Silicon micromechanical gyroscope has been improved furthermore.2. In the order to reduce the effect of rolling angular rate on the output signal of the micromechanical gyroscope, the paper has defined the parameter about the influence on the scale factor caused by the change of rolling velocity, and presented a method to restrain the influence. The experiment results have shown that the ratio is reduced nearly by 23 times and improves the scale factor consistency of the gyroscope.3. Though researching the relationship between phase difference, which is caused by output signal of the micromechanical gyroscope and accelerometer signal, and the deflection direction of the rotating carrier, the paper has proposed a method to determine the space deflection direction of rotating carrier based on the phase difference. Theoretical analysis and experimental results has verified the rationality and effectiveness of the method. Then the paper has analyzed the factors, i.e. rolling angular rate, the input angular, temperature and the demodulated accelerometer in the form of complex motion, which could influence the phase difference. Base on the rolling and input angular rate effecting phase difference, the paper has proposed composite phase difference compensation method. The test results have shown that the maximum absolute error of the compensated phase difference is less than 2°. The experiments have verified the validity of the compensation model.4. The micromechanical gyroscope output signal is a modulation signal including rolling, pitching and yaw angular rate. With the aim to demodulate the information to get the three angular rates used in the multi-channel control system of the rotating carrier, the demodulation algorithm of the micro-mechanical gyroscope output signal has been advanced and the simulation experiment has demonstrated the effectiveness of the algorithm. The results have shown that:(1) the algorithm can demodulate three angular rates i.e. rolling, pitching and yaw; (2) within the 5s, the maximum relative error between the demonstrated rolling rate and the actual rolling rate is less than 0.3%, the maximum absolute error between the demonstrated pitching rate and the actual pitching rate is 5.2°/s, the maximum absolute error between the demonstrated yaw rate and the actual yaw rate is 4.1°/s.5. Based on the above research, the paper has designed and implemented the micromechanical gyroscope attitude sensor prototype, whose core processing circuit is DSP2812. Then the prototype has been tested on the three-axis turntable, which can simulate the rolling missile. The results show that:the attitude sensor can sense rolling, yaw and pitching angular simultaneously and can output three angular rates in digital form directly to the host computer; the relative error of the demodulated rolling angular rate is less than 1%, the relative error of pitching (yaw) angular rate is less than 17%.