Research On Low-Frequency Vibration Isolation Platform Based On Negative Stiffness Theory

During the use of test equipment,vibration is often found,thus many adverse effects will be brought,such as noise pollution is increased,instrument detection is inaccurate,and usage rate is reduced.Therefore,vibration isolation has always been a technical problem that researchers have focused on to solve.At present,in order to eliminate the impact of such vibration interference,a passive vibration isolation device is generally placed under the vibration isolation instrument for vibration isolation.Among them,the vibration isolation platform is the most widely used because of its simple control,low cost,and easy replacement,so it is often used for low-frequency vibration isolation of precision instruments.However,because the equipment of traditional vibration isolation is limited by its own rigidity and a high natural frequency is obtained,low-frequency and ultra-low frequency vibration interference cannot be isolated by it.Therefore,the research of low-frequency vibration isolation platform is very imperative.Based on previous research experience and vibration knowledge,a permanent magnet repulsion type low-frequency vibration isolation platform with positive and negative stiffness in parallel is designed by this paper.Compared with the traditional linear system,the natural frequency of the parallel system will be reduced by 67%.The main content of this article is as follows:Firstly,the dual magnetic model is established by the theory of negative stiffness,and the model is parameterized.The static magnetic field module and transient magnetic field module in Maxwell software are used to simulate and analyze the model.The kinematics analysis of the inner magnetic column is performed.The negative stiffness value of the magnetic structure is calculated.Secondly,the overall stiffness tends to zero by the method of positive and negative stiffness offset.In this way,the parameter design and stiffness calculation of the positive stiffness spring element are carried out.The distribution and position control of the spring element are designed.The influence of damping on structural stability is analyzed.Thirdly,the overall structure of the low-frequency vibration isolation platform is parameterized,and the problem of the lateral offset of the platform support shaft is proposed.This problem can be effectively solved by connecting the flexible hinge up and down the negative stiffness mechanism.The selection of the flexure hinge is completed,and the workbench software is used for modal analysis.The steering stiffness and vertical stiffness are calculated,and various parameters of the flexure hinge are designed.Finally,a simplified Adams virtual prototype model is established.The dynamics of the linear system and the parallel system are analyzed respectively by using the Adams frequency sweep method and vibration module,and the influence of each influencing factor on the vibration isolation of the system is analyzed.The simulation results of the linear system and the parallel system are obtained,and the results verify that the positive and negative stiffness parallel system has a lower frequency vibration isolation performance,which meets the design requirements of this article.