Stick-Slip Friction And Its Dynamics Simulation Of Machine Tool Feed System

Machine tool is the main production equipment and the core of manufacturing industry.As an important part of machine tool,the accuracy of machine tool feeding system has an important influence on the machining accuracy of machine tools.When machine tool feeding system is running at low speed,it will produce stick-slip phenomena of fast-and-slow or time-to-time,which seriously affects the machining accuracy of machine tools.Therefore,a rigid-flexible coupling dynamic model of machine tool feeding system is established in this paper,and the stick-slip phenomenon of machine tool feeding system is deeply studied.The main work of this paper are included as follows:(1)The mechanical and mathematical models of the stick-slip phenomenon of the feed system are established.The mechanism of the stick-slip phenomenon and the factors affecting the stick-slip phenomenon are analyzed.Based on Yoshimura method and Hertz contact theory,the dynamic characteristic parameters of fixed joints and rolling joints of the feed system are calculated theoretically.(2)An experimental modal analysis and testing system was built.The parameter identification test of rolling joints of feed system is carried out,and the dynamic characteristic parameters of rolling joints are obtained.(3)The rigid body model of feed system and the flexible body model of ball screw,guide slider and rolling bearing are established.In ADAMS software,the rigid body model and the flexible body model are combined together,and the constraint relationship is added,thus the rigid-flexible coupling dynamic model of the feed system is established.The influence of the change of simulated cutting force and feed speed on the velocity fluctuation of the worktable of the feed system is determined.(4)A test platform for machine tool feed system and its measurement and control system are designed and developed.The functions include synchronous motion of two feed units,follow-up loading of pneumatic cylinder,acquisition and display of sensors data.Based on the test platform,the velocity fluctuation of the feed system worktable under different cutting forces and feed speeds is measured,and then the simulation results are compared to verify the correctness of the dynamic model.