RETRACTION: High-order iterative learning consensus tracking of nonlinear multi-agent systems with time-varying delays (Retraction of Vol 41, 2019)

In this paper, the tracking control problem of nonlinear multi-agent systems with time-varying delays and directed topology is discussed. Each agent of the system is influenced by time-delayed nonlinear terms and disturbances. It is supposed that the global Lipschitz condition is satisfied for nonlinear parts and the norm bounded condition is held for the disturbances. The design of control protocol considers the iterative learning control approach. Then, an improved high-order control scheme is proposed to deal with the consensus tracking, where the tracking trajectory is engendered via a virtual agent. A convergence condition that guarantees that the tracking errors asymptotically converge to an enough small interval is obtained by theoretical analysis. Furthermore, the norms of initial states deviation and disturbances tend towards zero, the norm of tracking errors tend towards zero as well. Finally, some simulation cases are given to clarify the validity of theoretical results.