Research On Construction And Trajectory Planning Of CNC System Of Ultra-precision Polishing Machine Tool For Hemispherical Resonator

Hemispherical Resonator Gyro(HRG)is a new type of resonator appear ed in the 1960 s because of its high precision,high reliability and long life characteristics.It has been widely used in the new generation of durable satellite navigation system.By studying the Coriolis Force Effect resulted from the radial vibration of the resonator,the HRG thus can be used to measure the rotation angle and its speed.As the most critical component of the HGR,the machining accuracy and surface quality of the hemispherical resonator directly affect the final performance of HRG.Therefore,the accuracy and quality of hemispherical resonator restricted the development and breakthrough of HRG in China.By exploiting the numerical control system to obtain the hemispherical resonators in ultra-precision accuracy,the working performance of HRG could be improved and thus then mass production of HRG could be achieved.The design of the open CNC system based on A3200 motion controller was firstly completed in this work.The structural characteristics of the magnetorheological polishing machine as well as the actual processing characteristics are considered in the selection of the system hardware equipment,design of the control cabinet circuit,and the implementation of the software function.Eventually,the CNC system software of the polishing machine tool is completed.The PID parameters are obtained based on the optimization of servo system parameters and the requirements of machine control performance.The response characteristics and dynamic of motion platforms are improved.Based on the principle and measurement method of positioning error compensation,the positioning error of X,Y and Z is measured by laser interferometer.The positioning accuracy of the system is improved by the corresponding compensation table which composed by the calculated compensation value.The three-dimensional model of hemispherical resonator was established and the numerical control program was created by UG program.The NC code for polishing is obtained by planning the polishing track and the post processing.The machining simulation of polishing process is completed by VERICUT software in order to verify the perfection of polishing trajectory and numerical control code.Based on polishing of the 3D-printed hemispherical resonator,the polishing trial of the fused silica material and hemispherical resonator were completed.The Repeatability deviation of the trajectories formed on the surface of the fused silica glass were 6.16 μm in two times.And the surface roughness Ra value of hemispherical resinator increases from the original 78.3nm to 14.3nm,the surface accuracy PV value increases from the original 0.5457μm to 0.3320μm.Control performance and processing accuracy of the system are tested.