Error Analysis And Modeling Of Coriolis Vibratory Gyro

Coriolis Vibratory Gyro is an important kind of inertial device, which not onlyhas all of inertial quality, but also has the features of high reliability, long life span,small volume, light-weight, high-precision that rotating-wheel gyros don’t have andcan be miniaturized. It is suitable for use in space and aviation applications. In thispaper, the dynamic model, the error sources, the error model of CVG, errormechanism caused by the defect of the resonator and the suppression method wereresearched.Firstly, the structures and dynamic models under ideal conditions ofhemispheric resonator and ring resonator are introduced. The dynamic model ofhemispheric resonator was established when non-uniformity of radius was taken intoconsideration, combined with the dynamic model of non-uniformity of density andquality factor, a general dynamic model suitable for all kinds of resonators of CVGwas given.Secondly, the dynamic model of CVG was analyzed and two main sources oferror, anisoelasticity and damping non-uniformity were defined. The rapidlychanging variables of the dynamics of the resonator were transformed into slowlychanging orbital elements and by defining energy and angular momentum, orbitalelements were associated with them. The dynamic equations of anisoelasticity anddamping non-uniformity were established by the transformation of parameters. Bycalculating the effect on the standing wave drift rate from non-uniformity of massand quality factor of HRG, the impact on the drift rate of CVG from elasticity non-uniformity and damping non-uniformity was given.At last, the error mechanism caused by resonator imperfections was discussed.The dynamics of the resonator can be described by transforming the system of twosecond order equations into a system of four first order equations using averagingmethod. In this way, the difficulty of analysis is simplified. Then the feedbackcontrol system of the resonator of CVG is established. Several kinds of feedbackcontrol loop such as frequency control loop, amplitude control loop, force-to-rebalance control loop were introduced. In modes of open-loop and force-to-rebalance control, the impact on scale factor and bias from resonator imperfectionswas calculated and the simulation results were given.