IMPROVED ROBUST H-INFINITY ESTIMATION FOR UNCERTAIN CONTINUOUS-TIME SYSTEMS

The design of full-order robust estimators is investigated for continuous-time polytopicuncertain systems.The main purpose is to obtain a stable linear estimator such that the estimationerror system remains robustly stable with a prescribed Hattenuation level.Firstly,a simple alterna-tive proof is given for an improved LMI representation of Hperformance proposed recently.Basedon the performance criterion which keeps the Lyapunov matrix out of the product of the system dy-namic matrices,a sufficient condition for the existence of the robust estimator is provided in terms oflinear matrix inequalities.It is shown that the proposed design strategy allows the use of parameter-dependent Lyapunov functions and hence it is less conservative than the earlier results.A numericalexample is employed to illustrate the feasibility and advantage of the proposed design.