Decentralized Adaptive PI Tracking Control for Interconnected Nonlinear Systems with Interconnection Delays

In this article, the problem of decentralized adaptive proportional-integral (PI) tracking control is investigated for interconnected nonlinear systems subjected to unknown inter-connection delay. An input-driven filter is firstly designed for interconnected nonlinear systems under consideration to identify unmeasurable state variables. The difficulties arising from interconnection delay are conquered by the appropriate Lyapunov-Krasovskii functions. After that, a PI controller with decentralized adaptive tracking is designed, making use of backstepping control technique, which ensures closed-loop systems signals uniformly ultimately bounded (UUB) and tracking error converging to a bounded compact set. In design procedures, unknown nonlinear functions are approximated by BLS (broad learning system). In the end, the results of simulation are regarded as verification of the presented method.