Study On Performance Of Precision Machine Tool Vibration Isolator Based On Nonlinear Quasi-zero Stiffness

The problem of broadband and micro-amplitude vibration from environment is the main reason that influences the machining accuracy of precision machine tool,it has become the key issue to improve the national equipment manufacturing level.Working environment of machine tool can be significantly improved through installing damper device between vibration source and equipment,but it is not suitable any more with the accuracy requirement of micron and submicron,as well as the working environment requirement of super-static,for passive vibration isolator.Developing higher quality vibration isolator of machine tool has become the hotspot and difficult issue for international manufacturers and researchers.According to the demand of precision machine vibration isolation,a novel mechanism of isolator,which can reduce broadband vibration effectively,is proposed with thinking of new structure and controllability.Design,analysis and test of the vibration isolator is also completed,the specific contents are as follows:(1)The requirement of precision vibration isolation technology was expounded,and a MR vibration isolator with squeeze mode was designed based on quasi-zero stiffness.For revealing the principle of stiffness decoupling and semi-active control,the structure and mechanism of the novel device were analyzing.(2)Combining fluid dynamics theory with machine dynamics theory,the LPM(Lumped Parameter Model)was set up.Then using two-way fluid-solid coupled nonlinear FEA(Finite Element Analysis),the main parameters of LPM were identified.This work lays the foundation for analyzing dynamic characteristic of vibration isolator.(3)FEM(Finite Element Model)of vibration isolator was established based on ALE dynamic mesh technology,then characteristic of flow field distribution was analyzed using the FEM.Based on the LPM,the dynamic stiffness and displacement transfer rate were studied.(4)Magnetic field controllability of vibration isolator was as constraint condition to complete Pareto optimization,which can improve the structure of vibration isolator based on MOGA(Multi-objective Genetic Algorithm).RSM(Response Surface Mode)was built,and comprehensive choice of Pareto optimal solution set was finished through analyzing the influence of the optimization variables on the optimizationtargets.Sample of vibration isolator was machined,and platform was built to test vibration isolation performance based on the sample.Theoretical analysis and experimental result show that the vibration isolator has small dynamic stiffness in low frequency and good vibration isolation effect in broadband,its performance can be improved through optimizing the structure parameters.This vibration isolator meets the requirement of precision machine tool.