Study On Stick-Slip Vibration Based On Rigid-Flexible Coupled Linear Motion Platform

With the development of high technology, the machine tool industry has developed rapidly, and the development of precision and ultra precision machine tools has played a decisive role. However, when the ultra-precision machine tool works under the conditions of low speed, overloaded or ultra-high speed, unstable flutter sports of the ultra precision machine tools which caused by stick-slip vibration phenomenon will make guide sports uneven, reduce its location accuracy and sensitivity, lead to dropping the processing precision and surface quantity of workpiece, also result in machine tool transmission system to generate additional dynamic load which causes tool wear intensification, and wear of guide rail is also increased. Therefore, studying the low-speed stick-slip and ultra-high-speed vibration problems not only has important theoretical significance, but also has great practical value to the development of the machine tool industry.This paper takes linear motion platform with two guides and four sliders as research object, applies virtual prototype technology to simulate the limit working conditions-low speed stick-slip and superhigh speed vibration, and deeply analyses the kinematics and dynamics characteristics, specific content researched as follows:(1) Through browsing relevant literature at home and abroad, the present situation of stick-slip vibration is summarized. The main methods of stick-slip vibration and domestic testing machine crawling device are introduced. The concepts related virtual prototype simulation technology and the application of virtual prototype software ADAMS are understood;(2) For the "low crawling" phenomenon appears on machine tool in the process of running at a low speed, a simple and efficient crawling motion model of single degree of freedom is established and carried on the mathematical description. The factors of producing crawling and critical speed are theoretically analyzed; (3) Dynamic modeling of linear motion platform with two guide and four sliders in the laboratory is established, using the finite element analysis software ANSYS to its guide for flexibility, generating modal neutral file. The modal neutral file is imported to ADAMS software as a flexible body, and combined with the rigid body model of linear motion platform produced in Solidworks. Rigid-flexible coupling model of linear motion platform is established, and imposed restriction to verify validity of the model;(4) In order to determine the influence which parameter changes make on the displacement velocity, acceleration of linear motion platform, low speed of machine designing and high-speed start, brake limit working conditions is kinematically analyzed. That leads to the crawling reason is that the transmission stiffness, dynamic and static stiffness, quality of the moving parts, system damping, and other physical factors. This paper reveals the essence of stick-slip vibration and suppression methods from theory.(5) Free vibration and forced vibration of linear motion platform are analyzed respectively based on ADAMS/Vibration. We can get their natural frequencies and modes through the software analysis. Motivate the two sliders on the before and rear rail, and different displacement, acceleration response results of slide will be obtained. Then to determine the changes which damping and stiffness parameters have an effect on the linear motion platform. Accrracy of simulation analysis is verified through natural frequencies comparion between modal experiment and simulation analysis.