Variable structure control of brushless DC motor using evolution strategy with varying search space

Variable structure control is a well known robust control algorithm and evolution strategy is used as an effective search algorithm in optimization problems. We propose a variable structure controller for a brushless DC motor using an evolution strategy with a varying search space. The evolution strategy with varying search space which depends on the fitness values at each generation, is used to tune the variable structure control parameters such as sliding surface gradient, saturation function boundary layer, unknown plant parameters and switching gain. Experimental results show that the proposed algorithm has accurate and robust performance with effective search ability.