Delay-Dependent Observers for a Class of Discrete-Time Uncertain Nonlinear Systems

This paper is concerned with the design problem of the systems with time-varying delay. Two Luenberger-like observers are proposed. One is delay observer which has internal time delay. This kind of observer is applicable when the time delay is known. The other is delay-free observer which does not use delayed information. This kind of observer is especially applicable when the time delay is not known explicitly. Delay-dependent conditions are derived for the existences of these two observers. A cone complementarity linearization algorithm is presented to calculate the observer gains. The effectiveness of the proposed methods is illustrated by numerical example.