Global Robust Practical Output Regulation for Nonlinear Systems in Output Feedback Form by Output-Based Event-Triggered Control

In this paper, we study the event-triggered global robust practical output regulation problem for a class of nonlinear systems in output feedback form with any relative degree. Our approach consists of the following three steps. First, we design an internal model and an observer to form the so-called extended augmented system. Second, we convert the original problem into the event-triggered global robust practical stabilization problem of the extended augmented system. Third, we design an output-based event-triggered control law and a Zeno-free output-based event-triggered mechanism to solve the stabilization problem, which in turn leads to the solvability of the original problem. Finally, we apply our main result to the tracking problem of the controlled hyper-chaotic Lorenz systems.