Decentralized adaptive robust controllers guaranteeing uniform asymptotic stability for uncertain large scale time-delay systems

The problem of decentralized robust control is considered for large-scale systems with delayed state perturbations and external disturbances. Here, the upper bounds of the delayed state perturbations and external disturbances are assumed to be unknown. The adaptation laws are proposed to estimate such unknown bounds, and by making use of the updated values of these unknown bounds, a class of decentralized local state feedback controllers is constructed. Based on the Lyapunov stability theory and Lyapunov-Krasovskii functional, it is shown that by employing the proposed decentralized adaptive robust controllers, the solutions of the resulting adaptive closed-loop large scale system can be guaranteed to be uniformly bounded, and their states can converge uniformly asymptotically to zero.