Approximation of Time-Delay Systems Using Curve Fitting Technique

This paper focuses on developing an analytical model for rational approximation of time-delay systems. The proposed model's attractiveness is in its simplicity and ease of implementation. The technique uses frequency response data of the pure time-delay model during the least square iteration while minimizing the Levy's cost function. The step-response characteristics of the proposed method have shown the best performance on various integer and fractional-order time-delay systems compared to the frequently used Padé approach. The numerical analysis in integral absolute error has further confirmed the best result of the proposed technique. This is true for all the considered integer and fractional-order time-delay systems.