Research On The Coupling Characteristics Between The Spindle And The Feed System Of Ultra-precision Machine Tool Based On Electromechanical Simulation

With the development of science and technology and socioeconomic progress,machine tools are developing toward ultra-precision.As we know,the most critical prerequisite for ultra-precision machining is the development of ultra-precision machine tools.But at present,the development of ultra-precision processing technology has entered into a bottleneck period.So,it is an important task to conduct research and analysis to the key components of ultra-precision machine to meet the requirements for ultra-precision machine tools,like improving the accuracy of ultra-precision processing,ensuring the quality of processed parts,extending the life of machine tools etc.The overall dynamic characteristics of the machine tool are affected by the dynamic characteristics of the machine tool spindles.There are some complex and various electromechanical coupling characteristics in the running process of machine tools,among which the mechanical system and the servo system greatly affect the processing performance of the machine tool.Therefore,we need to give serious consideration to the influence of mechanical system and servo control system on the dynamic characteristic of the machine tool,in addition to the influence of mechanical structure on the overall dynamic performance.As two of the most critical parts of ultra-precision machine tools,the dynamic characteristics of the spindle and guide rail have become the key problems in the field of ultra-precision machine tools,and also the difficulties to be overcome.For ultra-precision air static spindles and static rail systems,their mechanical structures and the dynamic characteristics of the servo system are simulated and analyzed respectively.We carried out modal study to obtain natural frequency and vibration pattern.Besides,we had harmonic response study to analyze the vibration amplitude.The model of the closed-loop servo system of spindle and rail are established,in which the parameters of the servo system are selected based on the PID control theory.Then,we carried out simulated analysis by using MATLAB/Simulink and it turns out the models have quick response and strong anti-jam capability.In this paper,we take the spindle and feed system in four-axis ultra-precision machine tool as spindle-feed system,whose performance has a huge impact on ultraprecision machine tools.Several possible coupling relationships between the spindle system and the feed system under the vertically distributed structure of the spindle-feed system are analyzed on the basis of the investigation for the mechanical and servo system of two separate systems.Dynamic mathematic models for spindle-feed system are established to obtain the natural frequency,vibration type,and vibration amplitude based on the finite element simulation with ANSYS.This study provides a general direction for future research about the coupling analysis in ultra-precision machine tools.