Patent ID: 8067863

Claim:
An apparatus comprising: a multiple phase linear electromagnetic actuator with a stator having repeating sets of ferromagnetic pales and corresponding sets of coils, for interacting with an armature having corresponding sets of permanent magnets to induce movement of the armature along a path, wherein; each pole is associated with one of a set of evenly spaced center points along an axis that runs along the length of the actuator in the direction of motion, and; a plurality of poles of a first set of poles are modified by either one or both of non-uniformly varying the displacement of the centers of the poles with respect to each associated center point and non-uniformly changing the width of the poles, wherein the modifications to the plurality of poles within the first set of poles are made symmetrically with respect to a nominal center of the first set of poles, and wherein: the modifications to the poles are small such that they do not substantially change the force output of the actuator.