The Analysis On Structural Performance Of Hrg Polishing Machine Tool And The Optimization Of Static And Dynamic Characteristics

The hemispherical resonator gyro (HRG) is the most ideal navigator widely used inall kinds of advanced strapdown inertial navigation systems in the21st century, and thehemispherical resonator is the core and sensitive element in the HRG, the precision ofwhich directly affects the performance of the gyro. At present, our country has notultra-precision machine tools specifically used for polishing hemispherical resonatorsdue to the blockade of foreign high end technology to China. The paper, taking theself-developed HRG ultra-precision polishing CNC machine tool as the research object,studies the static and dynamic characteristics directly influencing the processingperformance in depth. The research results have important significance to improvingstability and reliability of the machining accuracy of the machine tool.The simplified finite element model of the machine tool is established with thefinite element analysis software to do the static and the dynamic characteristics analysisin the research. In the static analysis, forced deformation of each part of the machinetool is studied so as to find that static deformation of the gantry, the supporting frame,the clamping part of tool spindle and the clamping part of working piece spindle isbigger, and they have certain effect on processability of the machine tool. In thedynamic characteristics analysis, the natural frequency is detected as the index of thedynamic performances. Based on the comparative analysis of the natural frequency andvibration modes, it is found that deformation vibration of the gantry, the supportingframe, the clamping part of tool spindle and the clamping part of working piece spindlehas a tremendous effect on the final machining accuracy of the machine tool.Meanwhile, in the dynamic testing, the modal test analysis of each part of the machinetool has been carried out. The experimental results verify the precision of finite elementdynamic simulation. Combined with results of static and dynamic characteristicssimulation analysis, the gantry and the supporting frame are recognized as mainstructural weaknesses of the machine tool and the clamping part of tool spindle and theclamping part of working piece spindle are considered as secondary weaknesses. Inaddition, during the experiment of dynamic characteristics of the machine tool effectingon the processing performance, it proves that dynamic characteristics of the machinetool can ensure the current requirements of machining accuracy, and better dynamicperformance of the machine tool also can further promote the stability of finalprocessing performance of the machine tool.At last, in order to control the stability of dynamic characteristics of the machinetool better, structural weaknesses of the machine tool are optimized by using the OPT optimization module of ANSYS software based on the APDL parameter designlanguage. The1st order nature frequency of the optimized gantry, the optimizedsupporting frame, the optimized clamping part of tool spindle and the optimizedclamping part of working piece spindle is increased88.3%,78.2%,25.2%and79.8%respectively so that they have better dynamic performances. At the meantime,considering processing requirements of the machine tool, another two kinds of overalllayout schemes are established based on the original overall layout plan of the machinetool. By way of static and dynamic characteristics comparative analysis of three kinds ofoverall layout plans of the machine tool, the optimal scheme is confirmed to offer strongtheoretical foundation and guidance for the improvement of the machine tool in thefuture.