Event-triggered tracking control for nonlinear systems subject to time-varying external disturbances

Event-triggered tracking control for a class of nonlinear systems with disturbances is investigated in this paper. Compared to existing related results, the nonlinearities only need to satisfy a generalized Lipschitz condition, and the time-varying external disturbances are allowed to be unmatched. By using finite-time disturbance observers, the finite-time estimation of the steady states is achieved to reduce the complexity of tracking control design. The event-triggered controller is designed by a new feedback domination approach, which can dynamically compensate for both errors caused by disturbances and the sampled-data implementation of the controller. A new Lyapunov stability analysis is given to show that all the signals of the closed-loop system are globally bounded and the tracking error is ensured to converge to a set, which can be made as small as desired by adjusting control parameters. Finally, a numerical example demonstrates the effectiveness of the designed scheme. (C) 2020 Elsevier Ltd. All rights reserved.