Decentralized adaptive practical tracking of nonlinear interconnected systems with dynamic input and output interactions

In this paper, the adaptive practical output tracking problem on a class of nonlinear interconnected systems is considered, in which the dynamic interactions and unmodelled dynamics depend on both the subsystem inputs and outputs. Under the assumption that both the references and their first-order derivatives are bounded, decentralized adaptive backstepping controllers have been proposed to make sure that all the signals in the interconnected systems are globally uniformly bounded, with the tracking errors converging to a small set around the origin.