Optimal Design of Short-Stroke Linear Oscillating Actuator for Minimization of Side Force Using Response Surface Methodology

Permanent magnet (PM)-type linear oscillating actuators (LOAs) are used in various types of equipment owing to their high efficiency, thrust density, and good control performance. However, the disadvantage of the LOA is the side force inevitably generated by the magnetic coupling structure of the stator and the PM mover. Therefore, side force reduction is essential at the design stage. This study manages the optimal side force design of a movable PM-type linear actuator using response surface methodology (RSM). Based on the Maxwell stress equation, three optimization variables were selected for the magnet shape, and experimental points were selected using the Box-Behnken design. The RSM was performed based on the results of the experimental points obtained through the finite element method. To prevent output reduction, the back electromotive force, which is directly proportional to the thrust, was selected as the constraint. The validity of the optimal design was verified through a characteristic comparison between the optimal and initial models along with experimental verification.