Hybrid Imperialist Competitive Algorithm with Simplex Approach: Application to Electric Motor Design

Imperialist competitive algorithm (ICA) is a population based metaheuristic inspired from imperialistic competition among empires. In order to improve its performances, we propose to hybridize ICA with the Nelder-Mead simplex method. The simplex algorithm is run if a stagnation criterion is satisfied, in order to help ICA escape local optima and to improve its intensification capabilities. The proposed hybrid ICA-simplex algorithm, called ICAS, is first analyzed and compared to the unmodified ICA and two well-known algorithms using the benchmark functions provided during the 2005 IEEE Congress on Evolutionary Computation. The results show the efficiency of the proposed hybrid algorithm. Then, it is used to optimize the design of a permanent-magnet machine used to motorize an electric scooter. The solution found by ICAS is shown to be better than those of several well-known metaheuristics.