Identification of fractional-order system based on modified differential evolution

Fractional order system can accurately describe systems by introducing additional degrees of freedom, but at the same time it increases the difficulty to identify the systems. In this paper, a modified differential evolution(MDE) is proposed, according to the response data of time domain, the rational fitness function is designed to identify the fractional order SISO(Single Input Single Output) system. The proposed method could identify both the parameters and the orders of the model, and is adaptive to the unknown system models. The simulation results show the accuracy and efficiency of this method.