Study On Measurement Method And Tuning Technology Of Fused Silica Micro Hemisphere Resonator

As a new type of solid wave gyroscope,fused silica microhemispherical resonant gyroscope(MHRG)has significant advantages such as high precision,small size,low power consumption and long life.It is one of the important development directions of high-performance resonant gyroscope in the future.The micro-hemispherical resonator(MHR)is the core component of the gyroscope.The inevitable material defects and manufacturing errors of the resonator will lead to frequency split and rigid axis offset in its working modes,which will directly reduce the bias stability and restrict the improvement of the performance of the gyroscope.In this paper,using the laser Doppler vibrometer(LDV)frequency test method and the femtosecond laser precision tuning technology,the precision tuning research is carried out around the frequency split and rigid axis offset of the fused silica MHR.The specific work is as follows:1.The tuning theory model of the MHR is established.Combining the defect formation mechanism of the resonant and the related theories of the micro-mass and stiffness perturbation model of the non-ideal resonant ring,the equivalent tuning model of the MHR is established.The influence of mass and stiffness changes on the frequency split and rigid axis orientation of the resonator is qualitatively analyzed.These all provide theoretical guidance for tuning technology.2.Investigate the effect of removing mass on frequency split and rigid axis orientation of the resonator.The tuning laws of mass removal on the resonator teeth-like tines are analyzed by modal simulation.The effect of the different radial distances and depths of the tuning grooves along the low-frequency axis on the frequency split is studied.And the effect of the various circumferential angles and depths on the orientation of the rigid axis is explored.Through these quantitative analyses,the coarse and fine tuning regions for the frequency split and the offset of the rigid axis of the resonator are summarized,which provides effective guidance for the subsequent tuning technology.3.Modal testing and femtosecond laser precision tuning of the MHR.The LDV testing system is built to test the main properties of the resonator,such as frequency split,orientation of the rigid axis,quality factor and damping axis,and the tuning laws of different groove positions are verified by the femtosecond laser tuning system.Combined with the tuning theory and laws,a precise tuning scheme for the MHR is formulated,and the femtosecond laser ablation process and testing system are used to carry out the precise tuning of the fused silica MHR.Finally,the frequency split of a resonator is tuned to below 90 mHz.