Design And Research On An Experimental Low-Frequency Vibration Isolator Using Active Pressure Compensation

Vibration is ubiquitous in our life.The existing technology can suppress high-frequency vibration well,but can not isolate low-frequency vibration effectively.From the butterfly effect of low-frequency vibration in subway to the stealth performance of military submarines,it shows that low-frequency vibration isolation is an urgent problem to be solved.Based on this engineering background,this paper carries out the research of low-frequency vibration isolation,and designs a low-frequency vibration isolator using active pressure compensation,which has the advantages of high load-carrying capacity,simple structure,wide applicability,easy processing,manufacturing and commercial production.And it can achieve high-static-low-dynamic stiffness characteristics.After the experimental platform is built,debugging and experimental verification are carried out,which have proved the feasibility of the vibration isolation principle.The main work of this paper is listed as follows:In the first chapter,the technical background and significance of this thesis is introduced.Through literature review,the current methods of low-frequency vibration isolation are summarized.They have a good effect of low-frequency vibration isolation to a certain extent,but with a strong limitation.In order to achieve the objective of heavy-loading,wide applicability and convenient commercial production,the research direction and content of this topic are established.In the second chapter,a low-frequency vibration isolator by using active pressure compensation is designed.Its principle and theoretical analysis are introduced.This chapter firstly establishes the dynamic model of the system.Then the active pressure compensation is applied to the model to calculate the transfer function of the dynamic system.The feasibility of reducing the equivalent stiffness of the system by using active pressure compensation is verified in vibration theory.In the third chapter,the mechanical structure design of experimental device is mainly introduced.The experimental device comprises an excitation device and a low-frequency vibration isolator,wherein the low-frequency vibration isolator is mainly composed of a worktable mechanism and a pressure compensation mechanism.According to the principle and the expected goals,concerning parameters calculation,structural design,parts processing and type selection of each component of the experimental device are carried out,and finally the experimental platform is built.In the fourth chapter,the implementation method of active pressure compensation in the experimental device is mainly introduced.In this chapter,test schemes of each component are given.Then,according to the principle of active pressure compensation,the components are integrated.And the oil flowing through the pressure chamber is regulated by speed feedback to maintain the constant pressure in the pressure cavity,so as to achieve the effect of zero-stiffness.In the fifth chapter,the low-frequency vibration isolator by using active pressure compensation is experimentally studied.Firstly,The signals of input force and output force of the system under different excitation frequencies are collected.Secondly,the experimental data are filtered,compared and analyzed,and force transfer ratios are calculated.At last,the natural frequency of vibration isolator is estimated by the relationship between transfer ratios and excitation frequencis.The low-frequency vibration isolation performance of the system is analysed by comparing the simulation results with the experimental data.In the last chapter,The work done is summarized.The results and limitations of the research are analyzed.And several proposals for further research and development are put forward.The future research work is prospected.