Global output feedback control for large‐scale time‐delay systems with inherent nonlinearities and measurement uncertainty

Abstract This paper investigates the problem of global state regulation by output feedback for a class of large‐scale nonlinear time‐delay systems with inherent nonlinearities and unknown measurement sensitivity. The uncertain nonlinearities are bounded by nonlinear growth of lower triangular unmeasurable (delayed) states multiplied by the unknown constant, polynomial‐of‐output and polynomial‐of‐input. Different from closely related works, the simultaneous existence of complicated nonlinearities and unknown measurement sensitivity makes the problem more involved and complex. Based on the dynamic gain scaling technique, we design a set of new adaptive output feedback controllers with a simpler structure by constructing two Lyapunov–Krasovskii functionals appropriately, which can globally regulate all states of the large‐scale systems. An illustrative example is proposed to demonstrate the validity of the presented control scheme.