Robust H∞ filtering for a class of discrete-time uncertain Nonlinear systems with state delay

This brief investigates the problem of robust H-infinity filtering for a class of discrete-time nonlinear systems with state delay and norm-bounded parameter uncertainty. The nonlinearities are assumed to satisfy the global Lipschitz conditions and appear in both the state and measured output equations. The problem we address is the design of a nonlinear filter which guarantees the asymptotic stability of the error system and reduces the effect of the noise signals on the filtering error to a prescribed level. A sufficient condition for feasibility is derived in terms of a linear-matrix inequality. An example is provided to demonstrate the applicability of the proposed approach.