Analysis On The Inhomogeneity And Micro Deformation Of Cylindrical Vibrating Gyroscope Resonators

The metallic shell resonator of the cylindrical shell vibrating gyroscope is a highly axisymmetric structure.However,the inhomogeneity of resonator results from material and geometry accuracy will lead to quality imperfections such as frequency split and node position variation,consequently influencing the overall performance of the gyroscope.In theory,resonators after proper material selection and heat treatment,as well as processing technology improvement,can reach high accuracy and performance.However,manufacture accuracy fails to reach good roundness because the mechanisms of possible micro deformation occurred in manufacture remain unclear.Besides,possible material inhomogeneity sometimes lead to large frequency split even in resonators with high geometric accuracy.In order to solve the above problems,the mechanism of material inhomogeneity and micro deformation is studied.The influencing rule of resonator inhomogeneity on node position has been studied by theoretical analysis,simulation and experimental verification.The main contents of this dissertation are as follows:1.The basic structure and operating principle of the cylindrical vibrating gyroscope are briefly introduced.The manufacture material and machining process are presented.Resonator inhomogeneity error and micro deformation are defined and their formation,relationship and influencing law are analyzed.2.Formation mechanism of the material inhomogeneity and its influencing rule on gyroscope performance are analyzed.By metallographic analysis on the microstructure of constant elastic alloy,comparison between metal round bars with different manufacture process and between different positions of a metallographic sample are implemented and their homogeneity are discussed.The results suggest that,grain slips are more common in edge section than center section and material inhomogeneity is radial distributed.Methods to eliminate the affections of material inhomogeneity are proposed.3.Resonator inhomogeneity errors are analyzed and clarified.Aiming at node position variation,which is one of the most important quality imperfections,resonator models with different kinds of errors are built and the node position variation rules in such conditions are studied by FEM method.Results are verified by acoustic test system.4.Forming reasons of resonator micro deformation resulting from axial clamping force are studied.Comparison of deforming mechanisms between different jigs is analyzed.By clamping force-deformation test based on a spoke-like force sensor,the mechanism of elastic deformation and resonator roundness variation caused by axial clamping force is revealed.Also,improvements on clamper and manufacture method are proposed.5.Theoretical analysis is implemented on the micro deformation mechanism of the resonator under the effect of radial cutting force when being machined.A radial force-deformation test platform is set up to analyze the plastic deformation as well as the resulting roundness error and frequency split,showing that a 140 N radial force can cause obvious plastic deformation.