Delay-dependent h∞ filtering for uncertain time delay nonlinear systems: an lmi approach

The problem of designing a delay-dependent robust H_infin filter for time delay Takagi-Sugeno fuzzy models is considered. The purpose is to design delay-dependent H_infin filters ensuring a prescribed H_infin performance level for the estimation error, irrespective of the uncertainties and the time delays. Sufficient conditions for the existence of a delay-dependent H_infin filter are given in terms of linear matrix inequalities. Membership functions´ (MFs) structural information is incorporated into the delay-dependent filter design to reduce the conservativeness of neglecting this information. It is shown that incorporating MFs´ structural information into the filter design does not lead to bilinear matrix inequalities, as in the control design case. Finally, a numerical example is used to illustrate the effectiveness of the proposed design techniques.