Robust adaptive output feedback tracking for a class of nonlinear tine-delayed plants

Abstract—Within the model reference adaptive control (MRAC) frame-work, a continuous adaptive output-feedback control scheme is developed for a class of nonlinear SISO dynamic systems with time delays which is robust with respect to unknown time-varying plant delays and to an external disturbance with unknown bounds. A special form of the Lyapunov-Krasovskii functional with a “virtual ” adaptation gain vector is introduced to prove stability. Index Terms—Robust adaptive control, nonlinear time-delay systems. I