Output feedback regulation of time-delay nonlinear systems with unknown continuous output function and unknown growth rate

Abstract

This paper is concerned with the global regulation via output feedback for the time-delay nonlinear systems with unknown continuous output function and unknown growth rate. Different from the existing literature, the output is perturbed by an unknown continuous function, and nonlinearities are upper bounded by unmeasured states multiplying an unknown constant and a polynomial of the output. A unified methodology is proposed to construct a new type of full-order observer with a dynamic gain by filtering unknown nonlinearities and time-varying delay. In light of a delicate scaling transformation, a combined system is derived to perform the one-step assignment of the controller instead of traditional backstepping recursive design. The stability analysis is completed by reductio and another scaling transformation with the upper bound of the dynamic gain. The efficiency of the proposed control scheme is demonstrated by two simulation examples including a practical one.