Adaptive output feedback control for large‐scale time‐delay systems with output‐dependent uncertain growth rate

Summary In this work, the problem of adaptive state regulation is addressed via output feedback for a wide class of large‐scale systems with strongly interconnected time‐delay nonlinearities. A design approach of partially decentralized adaptive controller is proposed, which gives a novel pair of reduced‐order observer and controller with nonidentifier‐based double adaptive gains. Compared with the existing results, the growth restrictions imposed on the interconnections are relaxed, where the growth rate includes not only an unknown constant but also the nonpolynomial functions of system output. The double dynamic gains are capable of compensating both the uncertain nonpolynomial growth rate and the unknown time‐varying delay. By constructing novel Lyapunov–Krasovskii functionals and combining dynamic‐scaling technique with 's lemma, it is shown that global adaptive state asymptotical regulation is achieved, that is all the closed‐loop signals are bounded, and the states of system and observer tend to zero as time goes to infinity. Finally, a simulation example is given to illustrate the proposed control scheme is independent of time delay and well universal.