A New Non-fragile H-infinity PI-Filtered-Error Adaptive Observer for a Class of Nonlinear Time-Delay Systems

In this paper, parameter and state estimation problem in time delay uncertain systems in the presence of observer gain perturbations is discussed which are linear in unknown parameters and nonlinear in states. A nonlinear non-fragile proportional-integral filtered-error adaptive observer is designed, and its stability conditions based on Lyapunov technique are derived. The optimal gain with maximum disturbance attenuation level among a solution set that satisfies the observer stability conditions is derived using linear matrix inequality approach. A numerical example is provided to demonstrate the effectiveness of the proposed method and the simulation results are provided.