An optimal design of magnetic actuators using topology optimization and the response surface method

Abstract

The magnetic actuator is a device that transforms electric energy to mechanical energy. By mechanical energy transformation, some part of the electric energy creates force, and the other part is stored within the ferrous material. An actuator with improved magnetic force can be designed by reducing the stored energy within the ferrous material at the core or the armature. Topology optimization based on the homogenization design method (HDM) is used for the initial design by determining the porous hole size of each element created. The homogenized magnetic permeability is applied in calculation of the magnetic energy stored. The magnetic energy is calculated by finite element analysis and the sensitivity is calculated mathematically by determining the effects of the magnetic energy according to the permeability change at each element. Repeating the process of the porous hole size determination by the sequential linear programming (SLP), eventually leads to a design of an actuator that makes the most improved magnetic force within the limited volume. The initial actuator model derived from topology optimization uses parameter optimization for detail designs. In parameter optimization design, the response surface method (RSM) based on the central composite design is used to obtain a clear final design.