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Wang X.,National University of Defense Technology | Fang Z.,Institution of Piezoelectric and Acousto optic Technology | Wu W.-Q.,National University of Defense Technology | Lou B.,National University of Defense Technology | Li Y.,National University of Defense Technology
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2011

The main gyroscopic effect of Hemispherical Resonator Gyro (HRG) is the standing waves precession in the hemispherical resonator shell, which is caused by the inertial rotation of the body. In order to analyze the effect of the solid wave procession in its resonator, the kinetic model of procession of the standing wave is presented under ideal condition based on the virtual work principle. Since the model is too complex to analyze, a similar system analysis theory is employed to make the complex kinetic procession model of the resonator be equivalent to two dimensional mass vibrations. Meanwhile, "slow-varying" and "fast-varying" variables are introduced to analyze the equivalent model parameters. Through comparing the figure of mass vibration to Lissajous figure obtained from the HRG pick-off electrodes, it is can be concluded that the similar system analysis theory is valid and correct.


Wang X.,National University of Defense Technology | Wu W.,National University of Defense Technology | Fang Z.,Institution of Piezoelectric and Acousto Optic Technology | Luo B.,National University of Defense Technology | Li Y.,National University of Defense Technology
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2012

Aiming at the quadrature drift problem in hemispherical resonator gyro (HRG), theoretical modeling and analysis of the drift mechanism in the HRG were carried out. The main factors that induce the drift of HRG outputs are frequency split and inhomogeneous damping. The inhomogeneous damping mainly introduces in-phase drift, while the frequency split mainly introduces quadrature drift. The in-phase drift, which is in phase with the Coriolis signal, can not be eliminated from the output of HRG, but only can be compensated through calibration. The quadrature drift can be eliminated with the method that changes the boundary stiffnesses of the resonator through introducing a quadrature control loop. In order to minimize the frequency split, the quadrature drift is taken as the feedback signal and an FPGA based digital control scheme was implemented. Experiment results show that the frequency split could be eliminated effectively through using the proposed method and the quadrature drift is suppressed.


Wang X.,National University of Defense Technology | Wu W.,National University of Defense Technology | Fang Z.,Institution of Piezoelectric and Acousto optic Technology | Luo B.,National University of Defense Technology | And 2 more authors.
Sensors (Switzerland) | Year: 2012

Temperature changes have a strong effect on Hemispherical Resonator Gyro (HRG) output; therefore, it is of vital importance to observe their influence and then make necessary compensations. In this paper, a temperature compensation model for HRG based on the natural frequency of the resonator is established and then temperature drift compensations are accomplished. To begin with, a math model of the relationship between the temperature and the natural frequency of HRG is set up. Then, the math model is written into a Taylor expansion expression and the expansion coefficients are calibrated through temperature experiments. The experimental results show that the frequency changes correspond to temperature changes and each temperature only corresponds to one natural frequency, so the output of HRG can be compensated through the natural frequency of the resonator instead of the temperature itself. As a result, compensations are made for the output drift of HRG based on natural frequency through a stepwise linear regression method. The compensation results show that temperature-frequency method is valid and suitable for the gyroscope drift compensation, which would ensure HRG's application in a larger temperature range in the future. © 2012 by the authors; licensee MDPI, Basel, Switzerland. 2012 by the authors; licensee MDPI, Basel, Switzerland.


Wang X.,National University of Defense Technology | Wu W.,National University of Defense Technology | Luo B.,National University of Defense Technology | Fang Z.,Institution of Piezoelectric and Acousto Optic Technology | And 2 more authors.
Sensors | Year: 2011

A novel design of force to rebalance control for a hemispherical resonator gyro (HRG) based on FPGA is demonstrated in this paper. The proposed design takes advantage of the automatic gain control loop and phase lock loop configuration in the drive mode while making full use of the quadrature control loop and rebalance control loop in controlling the oscillating dynamics in the sense mode. First, the math model of HRG with inhomogeneous damping and frequency split is theoretically analyzed. In addition, the major drift mechanisms in the HRG are described and the methods that can suppress the gyro drift are mentioned. Based on the math model and drift mechanisms suppression method, four control loops are employed to realize the manipulation of the HRG by using a FPGA circuit. The reference-phase loop and amplitude control loop are used to maintain the vibration of primary mode at its natural frequency with constant amplitude. The frequency split is readily eliminated by the quadrature loop with a DC voltage feedback from the quadrature component of the node. The secondary mode response to the angle rate input is nullified by the rebalance control loop. In order to validate the effect of the digital control of HRG, experiments are carried out with a turntable. The experimental results show that the design is suitable for the control of HRG which has good linearity scale factor and bias stability. © 2011 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.

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