Modeling and Compensation of Assembly Inclination Error of Micro Hemispherical Resonator Gyroscope Under Force-to-Rebalance Mode

Due to the micro hemisphere structure's small anchor point area, the micro hemisphere resonator and the Pyrex7740 glass electrode substrate are prone to tilt during the assembly process. The inclination angle of the assembly makes the electrode gap uneven, which will affect the control of the resonator and the detection of vibration signals, thereby reducing the accuracy of the gyroscope. In this paper, the formation mechanism of assembly inclination angle error of micro hemispherical resonator gyroscope (mu HRG) is analyzed in detail. The influence of assembly inclination error on electrostatic driving ability, capacitance detection ability, and electrostatic stiffness adjustment ability is revealed. Then, the dynamic model of second-order resonant state vibration with inclination error parameters is established. By measuring the capacitance when the resonator is still, the assembly inclination angle and inclination azimuth angle are identified by combining genetic algorithm with Nelder-Mead simplex. The correctness and effectiveness of the assembly inclination error parameter identification method are verified by experiments. The experimental results show that, compared with the uncompensated case, the bias instability of the mu HRG is reduced from 2.470 degrees/h to 2.322 degrees/h and the angle random walk (ARW) is reduced from 0.233 degrees/root h to 0.226 degrees/root h by using the gain compensation method.