Analysis and Control of 2-DOF Magnetic Levitation Stage Using Force Decoupling Theorem

This paper presents the analysis and implementation of a long-range magnetically levitated stage with two degree of freedom. The linear stage consists of a magnet array of Halbach type attached to the platen and three-phase coils of bottom side. Using a Halbach magnet array, magnetic flux can be concentrated on desired areas and cancelled in others. In this paper, a Halbach array of permanent magnets is used to levitate and propel a stage such that a finite element method can be used to compute the magneto static field of the Halbach array. Additionally, the magnetic field can be analytically designed, and a method for designing a linear motor with a Halbach magnet array is subsequently introduced. As induced flux is coupled, the application of a decoupled force algorithm is needed to make an independent force for the control of horizontal and vertical direction. Then by using this concept, the platen may be levitated by a permanent magnet linear motor. The device will allow a linear motion range of plusmn100 um in vertical direction and plusmn5 mm in horizontal direction with sub-micrometer scale positioning noise