Design And Experiment Of The Control System Of Triaxial Ultra-precision Lathe

With the development of advanced technology,the requirements on the processing level of parts are getting higher and higher,and the status of ultra-precision processing technology is becoming increasingly important.At present,the United States,Germany,Japan and some other countries have been able to realize the industrialization of ultraprecision machine tool equipment,and the ultra-precision machine tools can achieve a high level of processing.However,the ultra-precision machine tools are too expensive.Besides,the ultra-precision machine tools designed in China are far from developed countries in terms of control precision,stability and functional completeness.Therefore,it is of great significance to study the control system of ultra-precision machine tools.First,according to the functional requirements of ultra-precision lathes,the selection and verification of servo motors,drives,gratings,controllers and expansion cards were completed,and design of electric control system was carried out.Based on MFC,the upper computer interaction interface was developed modularly,which mainly includes machine tool detection module,program management module,parameter configuration module and JOG motion module.The software and hardware platform of the control system based on UMAC was built.Secondly,the modeling of linear motor and UMAC servo control algorithm were completed.The design and optimization of the current loop were carried out,and the simulation in Matlab/Simulink proved that the optimized current loop has the characteristics of fast response and no overshoot.Furthermore,the step responses and sinusoidal responses of the control system were analyzed.The simulation results showed that the control system has good steady state performance and dynamic performance.On this basis,the closed loop Bode diagram of the control system was drawn for the control system bandwidth,and the design of linear axis control system was completed.Thirdly,the debugging of each drive was completed.In the UMAC,manual setting was adopted to conduct step response debugging experiments and sinusoidal response debugging experiments,which verified the rationality of the simulation.Meanwhile,the simulation and experimental results showed that the control system has good control performance and satisfies the control requirements of ultra-precision lathe.In addition,to check the bandwidth design of the control system,the modal test experiment of each axis of the ultra-precision lathe was carried out.The experimental results showed that the bandwidth design of the control system was reasonable.Finally,the end face turning and cylindrical surface turning experiments of ultraprecision lathe were carried out.The surface morphology and roughness were analyzed,and the results showed that the control system designed by this paper has good control performance.Moreover,the bearing capacity of spindle thrust bearing was calculated for the serrated appearance in processing.Combined with the test results of machining quality,the influence of the structure and the control system on machining quality was explored,and the improvement suggestions were put forward for the existing defects of ultraprecision lathe.