ISSN:2164-6457 (print)
ISSN:2164-6473 (online)
Journal of Applied Nonlinear Dynamics
Miguel A. F. Sanjuan (editor), Albert C.J. Luo (editor)
Miguel A. F. Sanjuan (editor)

Email: miguel.sanjuan@urjc.es

Albert C.J. Luo (editor)

Department of Mechanical and Industrial Engineering, Southern Illinois University Ed-wardsville, IL 62026-1805, USA

Fax: +1 618 650 2555 Email: aluo@siue.edu

Derivation of Analytical Inverse Laplace Transform for Fractional Order Integrator

Journal of Applied Nonlinear Dynamics 6(2) (2017) 303--314 | DOI:10.5890/JAND.2017.06.013

Ali Yüce; Nusret Tan

Department of Electrical and Electronics Engineering, 44280, Inonu University, Malatya, Turkey

Abstract

There is considerable interest in the study of fractional order derivative integrator but obtaining analytical impulse and step responses is a difficult problem. Therefore all methods reported on to date use approximations for the fractional derivative/integrator both for analytical based computations and more relevantly in simulation studies. In this paper, an analytical formula is first derived for the inverse Laplace transform of fractional order integrator, 1/sα where α∈R and 0<α<1 using Stirling’s formula and Gamma function. Then, the analytical step response of fractional integrator has been computed from the derived impulse response of 1/sα. The obtained analytical formulas for impulse and step responses of fractional order integrator are exact results except the very small error due to the neglected terms of Stirling’s series. The results are compared with some well known integer order approximation methods and Grünwald-Letnikov (GL) approximation technique. It has been shown via numerical examples that the presented method is very successful according to other methods.

Acknowledgments

This work is supported by the Scientific and Research Council of Turkey (T¨UB˙ITAK) under Grant no.EEEAG-115E388.

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