Evaluation of the normal force of a planar actuator

Abstract

This paper describes a method to compute the normal force that acts on the mover of an electromagnetic planar actuator. The method is based on the Maxwell Stress Tensor and depends on the resulting magnetic field. The actuator has a mover with two permanent magnets and a ferromagnetic stator covered by two orthogonal armature coils. The mover is hold by a suspension system with linear bearings that enable bi-directional motion. A normal force is present and it depends on the magnetic flux density distribution produced by the permanent magnets and on the armature magneto motive force, since the latter contributes to that distribution. This paper focuses the analysis of that normal force in order to assess its effects on the actuator and in a way that allows the proper design of the mechanical parts that will be affected by it.