Optimal design of length factor for cross-coupled 2-DOF motor with Halbach magnet array

This paper introduces an optimal design for a cross-coupled two-degree-of-freedom (2-DOF) motor. Generally, Halbach magnet array can realize high magnetic loading. Therefore, higher thrust force and torque will be obtained by employing Halbach magnet array. The proposed motor has a shaft, the permanent magnets, helical windings, and two bobbins. This structure can independently realize linear and rotary motions. Also, the mover part is constituted of the shaft and the permanent magnets which are segment shape and magnetized to the radial or the axial direction. Two kinds of magnets (magnetizations of axial and radial directions) are alternately placed at the shaft to axial direction. By determining the length factor which is the ratio between lengths of two kinds of magnets, the maximum thrust force and maximum torque will be found. In this paper, the optimal design is verified by varying the length factor of these magnets and performing the finite element analysis (FEA).