Optimum design of end edge in discontinuous armature permanent magnet linear motors for automation transportation systems

Discontinuous armature permanent magnet linear motors (DAPMLMs) have recently been proposed to address problems such as the increase of material costs and maintenance fees. However, because of their discontinuous arrangement, the end edge of the armature produces considerable detent forces, which act as a thrust force ripple during operations, resulting in diminished control performance and causing vibration and noise in the machine. Therefore, in this paper, we propose a novel structure of stair-shaped auxiliary teeth applied on the armature end edge of DAPMLMs with concentrated winding, to reduce the end edge detent force generated by the armature discontinuous arrangement. Taguchi’s design of experiment (DOE) method is used for the optimum design of the stair-shaped auxiliary teeth. The experiment deign models are drawn from the orthogonal array of design parameters. Moreover, we analyze the influence of the design parameters on the objective function via 2-D finite element analysis, and verify the validity of the proposed stair-shaped auxiliary teeth by applying the optimum design values obtained via signal-to-noise ratio (S/N ratio) analysis.