Research On Vibration Reduction Mechanism And Optimization Of QZS Vibration Isolation Platform

At present,the problem of low frequency vibration isolation is still a big problem in vibration engineering.Therefore,it is of great significance to design a low-frequency vibration isolator with excellent performance.The quasi zero stiffness vibration isolator is composed of positive and negative stiffness elastic elements in parallel,so that the dynamic stiffness is zero at its static balance position.The quasi zero stiffness isolator has the advantages of large bearing capacity and low dynamic stiffness near its static balance position,which is conducive to low-frequency vibration isolation.In this paper,a new quasi zero stiffness(QZS)vibration isolator is proposed,and its feasibility is verified by the static and dynamic analysis of the system.In order to expand its low-frequency vibration isolation range,the system parameters are optimized.The principle prototype is made and the bench test is carried out.The specific research contents are as follows:(1)In this paper,a quasi zero stiffness vibration isolator of double-layer and three inclined linear spring is proposed,which is composed of two layers and three inclined spring mechanisms in parallel.The mathematical model of the vibration isolation system with quasi zero stiffness of the vibration isolator is established.The influence of different parameters on the static characteristics of the system is analyzed.The ideal static curve is obtained by modifying the system parameters.The stability of the system is determined by the criterion of system stability.(2)The analysis of vibration isolation frequency bandwidth of QZS vibration isolation system.The amplitude frequency characteristic of QZS system is analyzed,and the approximate solution is analyzed by harmonic balance method,and the quantitative result of the system is obtained.By analyzing the influence of different parameters on the amplitude frequency characteristics of the system,it is found that the system has jumping phenomenon.The influences of system parameters,damping ratio and amplitude of excitation force on jumping frequency are given.Taking the force transfer rate as the evaluation standard,the influence of different parameters on the vibration isolation performance of the system is analyzed.It is concluded that the resonance peak can be eliminated by properly increasing the damping ratio of the system.From the point of view of passive vibration isolation,the influence of displacement excitation of the base on the vibration isolation equipment is analyzed.It is concluded that when the critical damping ratio is selected,the system jump phenomenon can be eliminated.(3)Parameters optimization of QZS vibration isolation platform.The parameters of the isolator are optimized by the uniform design optimization method.Based on the optimization results,the principle prototype and its experimental platform are made.The stiffness displacement curve of the prototype before and after parameter optimization is obtained by static experiment,which is basically consistent with the theoretical analysis results.In the dynamic experiment,the experimental prototype before and after the optimization is tested on the vibration experimental bench,and the force transfer curve is obtained.By comparing the experimental results of the corresponding prototype before and after optimization,we can see that both of them have a certain low-frequency vibration isolation ability,and the optimized prototype has a lower initial vibration isolation frequency and resonance peak.