Study On Key Technologies Of Cupped Wave Gyroscope

The solid-state wave gyroscope has the advantages of high operation accuracy,small size, good stabilization and shock resistance, which is suit for the precision guidedweapons, especially for the tactical weapons and system. However, domestic solid-statewave gyroscopes couldn’t achieve the same performances as foreign ones, andexporting of high performance solid-state wave gyroscopes is forbidden by foreigngovernments. Therefore, researching the solid-state wave gyroscope technologies toimprove the ability of independent innovation is of great importance.Up to now, the highest performance solid-state wave gyroscopes are always madeof fused quartz, which needs high machining precision and assembly precision, andleads to high cost and low production efficiency, therefore, mass production is limited.In this dissertation, we explore the possibility of developing a novel cupped solid-stategyroscope based on piezoelectric effect. The cupped resonator of the gyroscope consistsof a high performance metallic structure and confectioning piezoelectric electrodes,which is fabricated by precision mechanical machining and precision adherencetechnologies. The cupped wave gyroscope has the advantages of simple manufacturingprocess, low cost, high performance and long life, which is a good candidate for massproduction.In this dissertation, we present the structure design, theoretical modeling andanalysis, fabrication process, control technology and performance test of the cuppedwave gyroscope. The main content includes:1. The cupped wave gyroscope based on piezoelectric effect is designed, and thebasic structure and operation principle are analyzed. The functions of vibration modeare obtained after analyzing the characteristic of vibration mode by theoretical methodand finite element method. Based on the mechanical analysis and electrical analysis ofthe vibrating structure and piezoelectric electrode, the piezoelectric actuator and sensormodel, lumped-mass model and lumped-stiffness model of the gyroscope are built.2. The dynamic function of the cupped resonator is established based on thetheoretical model. The dynamic responses of the active mode are achieved by assumedmode model method, dynamic magnification method and modal superposition method.The equivalent Coriolis moment the dynamic responses and detection signal of thesense mode are calculated, hence, the angular rate sensitivity of the gyroscope isachieved. By analyzing the effects of geometric and physical parameters on thesensitivity and natural frequency, the optimized structural dimensions of the cuppedresonator are25mm×18mm×1mm, the minimum dimension is0.3mm.3. The machining precision of the cupped resonator is planned based on theanalysis of the effect of fabrication errors on dynamic characteristics by finite element method. The C902alloy with constant elastic parameters is selected for metal structureof the cupped resonator. The mechanical machining process of the metal structure andthe adherence technology of the piezoelectric electrodes are designed. Several cuppedwave gyroscope samples are fabricated. The precision balanced method based oncup-bottom trimming is presented by analyzing the relationship of structure and naturalfrequency of the resonator. By using the precision balance method, the frequency splitof the resonator is minimized to0.01Hz, which satisfies the dynamic index of thegyroscope. The natural frequency of the fabricated prototypal cupped wave gyroscope isabout3954Hz.4. The equivalent circuit model of the resonator is deduced according to theelectromechanical coupling characteristics of the gyroscope, and the parameters of themodel are recognized from frequency response curves of the resonator. Based on thephase control method and ITEA index method, a stable resonant loop is designed toexcite the active mode of the resonator. The force balance control method of theresonator is researched and the angular rate signal is demodulated from the forcebalance control signal, which improves the bandwidth and linearity of the gyroscope.Based on the control technology above, the readout circuit of cupped wave gyroscope isdesigned and tested.5. A fabricated cupped wave gyroscope is characterized. The scale factor at roomtemperature is measured as50.5mV/°/s with a nonlinearity of216ppm in a range of±220°/s. The bias stability at room temperature is0.86°/hr and the angle random walk isabout0.07°/h1/2. At full operation temperature range, the frequency temperaturecoefficient is-6.5ppm/°C and the bias temperature coefficient is0.066°/s/°C. Theperformance indexes of cupped wave gyroscope reach tactical grade approximately.