Modeling and analysis of a novel magnetic levitation gravity compensator

摘要

In this paper, a novel cylindrical magnetic levitation gravity compensator is proposed, of which the mover is composed of several permanent magnet rings in the arrangement of Halbach structure and the stator is composed of one permanent magnet ring and four copper coils. The new vacuum compatible gravity compensator can be applied to the 6-DOF high precision magnetic levitation stage as the vibration isolation and leveling device. Firstly, the analytical model of the magnetic levitation gravity compensator is established. The flux density distribution of the Halbach magnet array rings is obtained by using equivalent current model. Then the expressions of magnetic levitation forces and vertical stiffness are derived. Secondly, finite element method (FEM) is used to calculate the magnetic levitation forces in order to verify the analytical model. The results from FEM are in good agreement with the ones from analytical model, which indicates that the analytical model is accurate and reasonable. In addition, a cooling system for the magnetic levitation gravity compensator is designed and the thermal field of stator part is calculated. Last, the temperature rise experiment is achieved.