Robust observer design for Lipschitz nonlinear discrete-time systems with time-delay

In this paper, robust H-infinity observer design for a class of Lipschitz nonlinear discrete-time systems with time-delay and disturbance input are addressed, where the Lipschitz condition is expressed in a component-wise rather than aggregated manner. It has been shown that both full-order and reduced-order robust H. observers can be obtained by means of the same convex optimization procedure with minimization of the disturbance attenuation upper bound gamma > 0. It is also shown that for a prescribed H-infinity-norm upper-bound gamma > 0, the tolerable Lipschitz bounds can be obtained by another convex optimization procedure.