Observer-based H∞ Controller Design for Discrete-time Nonlinear System with Mixed Time-delay

The problem of observer-based H_∞ controller design for a class of discrete-time mixed time-delay system with packet drop is investigated in this paper. The considered time-delay system not only has discrete delay but also has delay in distributed form. Attention of this paper is focused on observer-based H_∞ controller design such that the closed system is mean-square asymptotically stable with prescribed H_∞ disturbance attenuation level. Using Lyapunov-Krasovski method, sufficient condition for the existence of such a observer-based H_∞ controller is expressed in the form of linear matrix inequalities. Finally, a simulation example is used to demonstrate the effectiveness of our proposed methods.