H∞ Unknown Input Observers Design for a Class of Nonlinear Time-Delay Systems

Abstract: In this paper we address the problem of Unknown input Observer (UIO) for a class of nonlinear time delay systems. We propose an observer design method using a particular Lyapunov function that leads to solving a Linear Matrix Inequality (LMI) condition ensuring the H∞ convergence of the estimation error. Indeed, we use a Lyapunov function depending on the disturbances in order to avoid a specific obstacle in the stability analysis. Finally, a numerical example is provided in order to show the validity of the proposed method.