Research On The Quasi Zero Stiffness Of Vibration Isolator Based On The Magnetic Repulsive Force

The role of high precision equipment in various fields is becoming more and more important with the development of science and technology.But when the high precision equipment under dynamic carrier in the ferry transport and the working process,inevitably under various factors influence such as vibration,impact and continuous dynamic loading.Therefore,in order to ensure the accuracy of the high precision equipment,the research of reliable vibration isolation system becomes a urgent key technology to be solved.We found that the low frequency vibration is the main factor to affect the precision of high precision equipment through the survey,and the traditional linear vibration isolation system can't handle the contradiction between reduce the static displacement and lower the natural frequency,so it can't realize the low frequency and ultra-low frequency vibration isolation well.This paper put forward a new quasi-zerostiffness vibration isolation platform to guarantee the work precision of high precision equipment based on a provincial key project.The vibration isolation platform can not only reach the requirement of the QZS's stiffness characteristics of high static stiffness and low dynamic stiffness,and the experimental prototype test results can also achieve very good performance of vibration isolation,and the last part of the paper made a optimization of the QZS vibration isolation system and further realized the low frequency,ultra-low frequency vibration isolation in theory.This paper put forward a new kind of negative magnetic spring stiffness based on the traditional mechanism negative stiffness spring's shortcoming.The mechanical model of the negative magnetic stiffness spring is established and made statics analysis and finite element analysis.There are two cases that the magnet has radial magnetization and axial magnetization and the two cases were analyzed and compared respectively,the axial magnetization magnet was used to construct the negative magnetic stiffness spring.Then we made the dynamics analysis on the theory model of the negative magnetic stiffness spring,and we got the approximate expression of the QZS system's relationship between force and displacement based on ANSYS and MATLAB simulation fitting and established the dynamic equation.The force transmissbility and the displacement transmissbility were calculated by using the harmonic balance method,making comparisons to the corresponding linear vibration isolation system and found that the QZS vibration isolation system significantly reduces the starting frequency of vibration isolation.We designed and processed a QZS test prototype and made experiments of the QZS vibration isolator and its corresponding linear vibration isolator respectively on the vibration table.Then we got two transmissbility curves to be compared and found that the vibration isolation effect of the QZS vibration isolator at low frequency is much better than its corresponding linear vibration isolator,so it is in line with theoretical research.Finally,we designed a nonlinear spring and with linear spring in parallel to optimize the positive stiffness spring system.We made the dynamics analysis of the optimized QZS vibration system to get the transmissbility of the optimized system and compared with the non-optimized system on the same damping ratio and the same excitation amplitude.After theoretical calculation we found that optimized QZS system can be further realize low frequency vibration isolation in theory.