Identification of Fractional-Order Transfer Functions Using a Step Excitation

This brief proposes a new method for the identification of fractional-order transfer functions based on the time response resulting from a single step excitation. The proposed method is applied to the identification of a 3-D RC network, which can be tailored in terms of topology and composition to emulate real-time systems governed by fractional-order dynamics. The results are in excellent agreement with the actual network response, yet the identification procedure only requires a small number of coefficients to be determined, demonstrating that the fractional-order modeling approach leads to very parsimonious model formulations.