Mahmoud M.S.Zribi M.October University for Modern Science and ArtsAmer StreetMesaha SquareDokki-GizaEgypt; Department of Electrical EngineeringCollege of Engineering and PetroleumKuwait UniversityP.O. Box 596913060 SafatKuwait2020-01-252020-01-252003457906https://doi.org/10.1016/S0045-7906(01)00023-4https://www.sciencedirect.com/science/article/pii/S0045790601000234ScopusThis paper investigates the design of robust observer-based controllers for a class of uncertain linear time-lag systems. The uncertainties are assumed to be norm-bounded. We extend the previous results on quadratic-cost control to the case of observer-based control for uncertain systems with unknown state and input time-lags. By introducing an appropriate definition of quadratic stability for uncertain time-lag systems, it is shown that observer-based controllers can be constructed via solutions of linear-matrix inequalities. A simulation example is given to illustrate the theoretical developments. 2002 Elsevier Science Ltd. All rights reserved.EnglishObserver-based controllerRobustTime-lag systemsUncertainComputer simulationLinear control systemsRobustness (control systems)System stabilityTime lag systemsUncertain systemsArticlehttps://doi.org/10.1016/S0045-7906(01)00023-4