Electromechanical Coupling Modeling And Performance Research Of The Drive At Center Of Gravity Feed System

As a key functional component of NC machine tool, the static and dynamic performances of the feed drive system directly affect the machining accuracy and cutting efficiency of the machine tool. The drive at center of gravity(DCG) feed system, through optimizing the driving force point, can significantly reduce the deformation of the drive components, reduce the vibration of the feed system, reduce the load on the single ball screw and improve the axial stiffness of the feed system. Therefore, the center of gravity driven feed system has excellent ability of the resistance to deformation and the high speed and high acceleration. The dual axis DCG feed system of the precision horizontal machining center is studied in the dissertation. The influence law of the mechanical structure parameters on dynamic characteristics of the DCG feed system is developed through theoretical modeling and electromechanical coupling simulation analysis, which lays the theoretical and technical foundation for design and optimization of structure. The main works are as follows:Considering the stiffness and damping of the feed system, axial and torsional vibrations of the ball screw, the 3D parametric dynamic model of the DCG feed system is modelled using the lumped mass method. Then the simulation model of the DCG mechanical system based on MATLAB/Simulink is constructed by the state space method.The mathematical model of dual-driving synchronous servo system is established. The electromechanical coupling model of the DCG feed system is constructed based on input-output relationship of the servo system and mechanical system.Based on the simulation analysis, the influence law of the mechanical structure parameters, ball nut stiffness, change of cutting position on the dynamic characteristics of the DCG feed system is developed.The finite element model of the DCG mechanical system is established using SAMCEF software. The linear static analysis, modal analysis and harmonic response analysis of the mechanical drive system are carried out to obtain the influence law of the mechanical structure parameters on the static and dynamic characteristics of the system.