Multi-Functional Micro-Machined Gyroscope And Its Appilicaiotn

In1990s, with the development of the microelectronics technology, a wide variety of micro-machined gyroscopes appeared. Most of designs use the Coriolis force generated by the roll of the vibrational mass driven by the base to sense the angular rate of the carrier. This kind of gyroscopes may only sense one angular rate in one direction. Compared to those micro-machined gyroscopes, the paper studies the multi-functional micro-machined gyroscope which generates the gyroscope effect driven by the roll of carrier, and sense the roll angular rate in the vertical axis direction of rotating carrier and the transverse angular rate in the perpendicular direction of vertical axis of rotating carrier. In addition, the transverse angular rate can be decomposed into the yaw angular rate and pitch angular rate with the geographic coordinates of reference. Therefore, multi-functional micro-machined gyroscope can sense angular rate in three directions, and the signal of gyroscope can be calculated into the five parameters, including the transverse angular velocity, azimuth angle, yaw angular rate, pitch angular rate and roll frequency, which has the functions of three the general rate gyroscopes mounted vertically and fits for the attitude control of rotating aircraft.In this paper, the multi-functional micro-machined gyroscope and its application are discussed. The study includes:the mechanism of multi-functional micro-machined gyroscope sensing yaw, pitch and roll angular rate in three directions; the improvements of structure of multi-functional micro-mechanical gyro design and production process; the performance characteristics of multi-functional micro-mechanical gyro in one direction motion, the coning motion and variable roll speed motion; the method of multi-functional micro-mechanical gyro signal extracting five parameters; the signal demodulation algorithm of multi-functional micro-machined gyroscope; the application of multi-functional micro-machined gyroscope in the attitude control of rotating aircraft. The above-mentioned researches are difficult, practical, and innovative.(1) The dynamics model and error model of the non-driven structure micro-machined gyroscope are deduced. The theory explains the mechanism that the gyroscope can sense the angular rates in three directions. The simulation obtains the first, second and third orders of the natural frequency of the gyroscope according to the design parameters of the gyroscope.(2) The original masks which use the "step-by-step alignment" marks have the problem of cumulative deviation. The "one-step alignment" marks are presented to eliminate the cumulative deviated caused by the former alignment deviation and improve the consistency of the chip production. Solve the problems of in the photolithography and wet etching process, including that the exposure time is too long, the photoresist problem, and the pits on the chip surfaces.(3) The theories and experiments verified the performance characteristics of multi-functional micro-mechanical gyro in one direction motion, the coning motion and variable roll speed motion. In the coning motion, the signal frequency of gyroscope is not equal to the roll frequency of rotating aircraft, which means that the gyroscope measures the absolute motion of the rotating aircraft. The signal frequency of gyroscope (absolute frequency of exercise) equal to the combination of the roll frequency of the rotating aircraft (frequency of relative motion) and the frequency of coning motion (frequency of convected motion). In variable roll speed motion, the scale factor and the initial phase of the gyroscope change. The polynomial fittings of scale factor and the initial phase are presented. The transverse angular velocity and azimuth are calculated with the scale factor and the initial phase corresponding to the roll frequency.(4) The method for solving transverse angular rate, azimuth, yaw angular rate, pitch angular rate and roll frequency from the signal of the multi-functional gyroscope is presented. The envelope of the gyroscope signal is proportional to the transverse angular rate. The azimuth is obtained by the phrase difference of the gyroscope and the accelerator. The transverse angular rate is divided along the azimuth into yaw and pitch angular rate. The yaw, pitch and roll angles are obtained by the integration of the yaw, pitch and roll angular rate.(5) The algorithm based on Matlab program is written, the validity of which is verified by the three-axis turntable test. The character that the two signals of two multi-functional micro-machined gyroscopes installed vertically are orthogonal to each other is presented. The two signals can be used to instead of the Hilbert transform in the original algorithm and effectively improve the real-time character of the algorithm and is tested by experiments. The graphical user interface of the micromachined gyroscope signal solver software was programed and applied the software copyright to protect the novelty of algorithm,.(6) Two prototypes of the multi-functional micro-machined gyroscopes are tested. The measurement range of the yaw and pitch of the two prototypes is positive-negative10degree, the measurement error of yaw and pitch of the two prototypes is less than positive-negative1degree, which can be used in the multi-channel control of the rotating aircraft. The theoretical analysis for the gyroscope used in the single-channel control of the rotating aircraft is introduced. The gyroscope signal adds the linearized signal, so the amplitudes of gyroscope signal change into the time of across zero.(7) The effects of linear vibration and shock on the multi-functional micro-machined gyroscope are studied. The bias of the gyroscope changed about1mV during the before, in and after the linear vibration test. The analysis on the cause of the shock-response signal shows that the pendulum of gyro deflects about the torsion girder when it is shocked in its thickness direction due to its mass off center. The method of increasing the thickness of the torsion girder of gyroscope is presented to reduce the deflection angle of pendulum under unit shock acceleration. The experiment results show that thickening the torsion girder by about 1/3times can reduce the amplitude and width of shock-response signal by about18times.