Research On Technology To Improve The Quality Factor Of Fused Silica Micro Hemispherical Vibrating Gyroscope

Gyroscope is the core device in the fields of motion measurement,inertial navigation,and guidance control.Featuring large dynamic range,high precision,good impact resistance,small size,low cost and low power consumption,the micro hemisphere resonant gyroscope(HRG)is one of the most promising gyroscopes.Improving the quality factor has a direct impact on the key performance indicators such as the mechanical sensitivity and zero-bias stability of the micro hemispherical resonator gyroscope.In this paper,based on the basic loss mechanism such as thermal elastic loss,surface loss and support loss,combined with surface metallization,assembly and packaging and other related processes,the mechanism and method of improving the quality factor of micro hemisphere resonant structure were studied,and process and technical support for the manufacture of high performance micro gyroscopes were provided.The main research contents are as follows:1.The basic factors affecting the quality factor of the micro-hemisphere resonance structure were analyzed.The basic concepts and test methods of quality factor were introduced.Combined with the manufacturing process of micro hemispherical resonator structure,the potential effects of surface metallization and structural vacuum packaging on the quality factor were analyzed.2.The processing and assembly process of the micro hemisphere resonant structure was optimized.The basic method of micro hemisphere resonant structure and electrode assembly was introduced.An adjustable alignment platform based on capacitance detection was designed and fabricated to solve the problem of inconsistent hoop capacitance gap.The process of realizing the resonant structure and electrode substrate micro-assembly by gold-tin bonding was explored,and the stable assembly of the resonant structure and the electrode was realized.3.The effect of surface metallization on the quality factor of the resonant structure was studied.The finite element model of the metal film-quartz composite layer structure was established.It was obtained that the thinner the surface metal film layer was,the higher the quality factor of the resonant structure was by simulation and experiment.The annealing structure of the surface metallized resonant structure was annealed.The quality factor after annealing was up to 112.63%,which confirmed thatthe annealing process is effective for improving the quality factor of the resonant structure.4 The influence of structural packaging on the quality factor of micro hemisphere resonant structure was explored.The quality factor of the micro hemispherical resonator gyroscope with pressure was obtained by the vacuum degree experiment.The experimental results were basically consistent with the theoretical model.The quality factor after encapsulation was up to 243.7% and the lowest increase was 86.3%,compared with that was under the 5Pa vacuum environment.