The Structural Design And Analysis Of A Novel Magnetic Levitation Stable Attitude Platform

The novel magnetic levitation stable attitude platform adopts micromotion isolation platform for the axial and radial three-degree-of-freedom translational vibration isolation,and uses macro-motion platform for the radial two-degree-of-freedom deflection,which shows the advantages of the high precision,active control and vibration suppression,making it an ideal mechanism for large-angle deflection and high-precision stable attitude.In this paper,to tell the new magnetic levitation stable attitude platform better,the main research contents are as follows:(1)To overcome the shortcomings of low positioning accuracy,complex structure,high cost and large size of traditional platform and achieve the goal of high precision steady attitude,a new magnetic levitation steady attitude platform scheme integrating micro-motion isolation platform and macro-motion platform has been proposed,carrying out the comparative analysis of magnet steel and paramagnetic ring materials used in the steady attitude platform.(2)To select a gravity compensator suitable for the micro-actuated vibration isolation platform,the passive magnetic bearing scheme of transverse air gap and vertical air gap basic configurations have been compared,selecting the axial magnetically charged suction type passive magnetic bearing scheme as the gravity compensator of the micro-actuated vibration isolation platform as well as introducing its scheme and working principle.What’s more,with the equivalent magnetic charge method,the mathematical model of the radial force and axial bearing capacity of the passive magnetic bearing has been established.On this basis,the radial adjustment gap of the passive magnetic bearing is designed by the calculation method,and the gravity compensation of the passive magnetic bearing model is verified by the numerical calculation method and finite element.The results show that the designed passive magnetic bearing is able to achieve the goal of gravity compensation in the radial adjustment range of the micro-motion vibration isolation platform.(3)To realize the high-frequency large-angle deflection of the moving iron type macro moving platform radially in two degrees of freedom,three spherical Lorentz force magnetic bearing solutions have been proposed for the kinematic-iron macro-stage with ordinary asymmetric type,polymagnetic asymmetric type and symmetric type,and the superiority of the symmetric spherical Lorentz force magnetic bearing solution is determined by the comparison analysis of finite element method.Based on the equivalent magnetic circuit method,the mathematical models of deflection torque and deflection current stiffness of symmetrical spherical Lorentz force magnetic bearing have been established,and the key variables affecting the deflection torque and deflection current stiffness have already been analyzed.When the total thickness of the unilateral paramagnetic ring and magnet are fixed and the air gap width could be constant,the feasible ratio parameters have been analyzed and the optimal ratio of magnet magnet magnetizing length to paramagnetic ring thickness has been determined.(4)Based on the defects of large kinetic mass and high rotational inertia of the moving iron type macro moving platform,a moving coil type macro moving platform has been proposed,and the magnetic force line diagram,flux density cloud diagram and air gap axis center flux density diagram,processability and economy of the embedded cylindrical magnet spherical Lorentz force magnetic bearing scheme and the embedded spherical magnet spherical Lorentz force magnetic bearing scheme have both been compared and analyzed.The embedded cylindrical magnet spherical as well as the superiority of the Lorentz force magnetic bearing scheme has been determined.In order to compensate the defect of column surface magnets with column shell air gap,a scheme of adding magnetic isolation spherical washers on both sides of the column surface magnets has been selected.The mathematical model of the deflection torque of the spherical Lorentz force magnetic bearing with embedded cylindrical magnets has been established by using the magnetoresistive partitioning method and the integration method.The finite element method has been used to optimize the design of the spherical Lorentz force magnetic bearing with embedded cylindrical magnets,and the final structural parameters of the magnetic bearing have been determined.A comparative analysis of the moving-coil and moving-iron macro-stage has been conducted to determine the superiority of the comprehensive performance of the moving-coil macro-stage,and finally a deflection test experiment has been done for the magnetic levitation stable attitude stage.