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Mathematical Problems in Engineering
Volume 2012 (2012), Article ID 635709, 13 pages
Research Article

Robust Observer Design for Takagi-Sugeno Fuzzy Systems with Mixed Neutral and Discrete Delays and Unknown Inputs

1Department of Engineering, Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway
2Laboratory of Modeling, Information and Systems, University of Picardie Jules Verne, Amiens, France

Received 30 September 2012; Accepted 3 November 2012

Academic Editor: Peng Shi

Copyright © 2012 Hamid Reza Karimi and Mohammed Chadli. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A robust observer design is proposed for Takagi-Sugeno fuzzy neutral models with unknown inputs. The model consists of a mixed neutral and discrete delay, and the disturbances are imposed on both state and output signals. Delay-dependent sufficient conditions for the design of an unknown input T-S observer with time delays are given in terms of linear matrix inequalities. Some relaxations are introduced by using intermediate variables. A numerical example is given to illustrate the effectiveness of the given results.