Delay-dependent robust H∞ and L2-L∞ filtering for a class of uncertain nonlinear time-delay systems

This note presents delay-dependent robust H_∞ and L₂-L_∞ filter designs for a class of nonlinear systems with multiple time-varying delays in the state and parameter uncertainties residing in a polytope. The nonlinearities are assumed to satisfy global Lipschitz conditions. Attention is focused on the design of robust full-order and reduced-order filters guaranteeing a prescribed noise attenuation level in an H_∞ or L₂-L_∞ sense. The admissible filters can be obtained from the solution of convex optimization problems in terms of linear matrix inequalities, which can be solved via efficient interior-point algorithms.