Structure Disgn Of Magnetic Vibration Isolator Based On Equivalent Charge Model

Magnetic vibration isolator uses controllable magnetic field to support the isolated object,thereby reducing the interference of ground vibration.Therefore,magnetic vibration isolator has great practical value in the lithography syst em,precision machining and measurement,and it receives extensive attention and research in recent years.This paper proposes an improved analytical model,which can be used for designing magnetic vibration isolator,the improved model could improve the design speed while ensuring the design quality.Based on this analytical model,this paper designs a low stiffness,large load magnetic vibration isolator to reduce the impact of ground disturbance.To conclude,main result of this paper are as follows:Firstly,the analytical model is improved.Aiming at the limited accuracy of traditional analytical model,the relative permeability of permanent magnet is taken into account in the establishment of the model,the influence of external magnetic field on solving the interaction force is analyzed,and an improved analytical model based on equivalent charge method is proposed.Secondly,the magnetic vibration isolator is designed based on the improved analytical model.By comparing the stiffness and load capacity density of permanent magnet arrays with different structures,the better array was selected.After determining the structure,the stiffness,bearing capacity density and other characteristics of the vibration isolator are taken as optimization objectives to optimize the size of the magnetic vibration isolator.Thirdly,the errors in the magnetic suspension vibration isolator system are analyzed,including mechanical errors and measurement errors.Among them,machining errors of permanent magnet and support frame,magnetization errors of permanent magnet,assembly errors of permanent magnet and support frame will have a great impact on the bearing capacity results of the vibration isolator.Therefore,when processing the experimental data,it is necessary to measure the actual size of the prototype of the magnetic vibration isolator.After eliminating these errors,the improved analytical model is used again to establish the model of the vibration isolator.Finally,the experiment of the magnetic vibration isolator is carried out.Through experiments,it is verified that the carrying capacity of the isolator is 1065.80 N,the vertical stiffness is 702.84N/mm,which all met the requirements of the design objective.The vibration isolator could effectively reduce the impact of ground vibration.The difference between the measured value and the finite element simulation with error is 1.32%,which is in good agreement.The difference between the improved analytical solution and the finite element simulation is considered as 0.06%,and the difference between the traditional analytical solution and the finite element simulation is considered as 11.12%,which proves that the improved analytical model can effectively improve the modeling accuracy.