Title: A unified approach for design of indirect adaptive output-feedback fuzzy controller

Authors: Abdesselem Boulkroune, Mohamed Tadjine, Mohammed M'Saad, Mondher Farza

Addresses: Department of Automatic, University of Jijel, Jijel 18000, Algeria. ' Department of the Electric Engineering, ENP, Algiers, Algeria. ' GREYC, UMR 6072 CNRS, Universite de Caen, ENSICAEN, 6, Bd Marechal Juin, 14050 Caen Cedex, France. ' GREYC, UMR 6072 CNRS, Universite de Caen, ENSICAEN, 6, Bd Marechal Juin, 14050 Caen Cedex, France

Abstract: In this paper, an indirect adaptive fuzzy output-feedback control based on the observer is presented for Single-Input Single-Output (SISO) uncertain non-linear systems. On the basis of the estimation of the tracking error, and without resorting to the famous Strictly Positive Real condition or the filtering of the observation error, a Proportional-Integral law for updating the adjustable parameters is proposed. Then, a unified observer is used to estimate the tracking error. Indeed, the corrective term of the proposed observer involves a well-defined design function which is shown to be satisfied by the commonly used High-Gain (HG)-based observers, namely, for the usual HG observers and the Sliding Modes observers together with their implementable versions. The Lyapunov synthesis approach is used to guarantee a Uniformly Ultimately Bounded property of the observation and tracking errors, as well as of all other signals in a closed-loop system. The viability and the efficiency of the obtained fundamental results are clearly illustrated through a numerical simulation involving the usual benchmark example of the fuzzy control community.

Keywords: adaptive control; fuzzy control; high-gain observers; nonlinear system; proportional-integral law; sliding mode observer; uncertainty; tracking errors.

DOI: 10.1504/IJISTA.2008.018168

International Journal of Intelligent Systems Technologies and Applications, 2008 Vol.5 No.1/2, pp.83 - 103

Available online: 05 May 2008 *

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