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[Display omitted] • A noval event-triggered control strategy is developed by integrating backstepping method and emulation method into the event-triggered control study the distributed tracking of nonlinear MASs. Compared with the single-agent system, the control design in this paper is more complicated since that its's necessary to consider information interaction between each agent. • The event-triggered control strategy saves more communication and computing resources compared with the periodic sampled-data control schemes. In addition, The introduction of event-triggering mechanism, on the one hand, leads to complex discontinuity of the system, which renders the analysis and synthesis of the MASs more difficult than MASs with continuous controllers. • The dynamic of the i th follower discussed in this paper contains N i integrators and nonlinearities, which is more general and more complex than linear MASs, and first-order and second-order MASs. The existence of nonlinear functions makes the design and construction process of event-triggered controller more complicated. This paper investigates the problem of distributed output tracking for nonlinear multi-agent systems via event-triggered control under a directed graph topology inspired by the advantage that event-triggered control can effectively save resources and the wide application of multi-agent systems. By backstepping and emulation method, the event-triggered control strategy is put forward, by which a series of event-triggered controllers and event-triggering mechanisms with absolute or relative threshold are designed. An inevitable problem on event-triggered control, called Zeno phenomenon, is avoided by guaranteeing a positive minimum inter-execution interval. We can see from the event-triggered control strategy that the closed-loop system has a unique solution and tracking error could be adjusted to arbitrarily small while ensuring the boundedness of all states. Finally, a numerical example is shown to verify the validity of the conclusion. [ABSTRACT FROM AUTHOR]

We study the distributed output‐feedback tracking control problem by linear sampled‐data control for nonlinear multi‐agent systems with unmeasurable states in this paper. Noting that sampled‐data control can effectively reduce implementation cost and time, we develop a novel linear sampled‐data high‐gain homogeneous domination control strategy by integrating backstepping method and high‐gain homogeneous domination method into sampled‐data control. A series of linear sampled‐data output‐feedback controllers and reduced‐order observers are designed to ensure that the output tracking errors can be tuned arbitrarily small while all states of the closed‐loop system are globally bounded. A numerical example is given to verify the effectiveness of the sampled‐data strategy. [ABSTRACT FROM AUTHOR]

Summary: This paper is devoted to the global stabilization via output feedback for a class of nonlinear systems with unknown relative degree, dynamics uncertainties, unknown control direction, and nonparametric uncertain nonlinearities. In particular, the unknown relative degree is without known upper bound, which renders us to research for a filter with varying dimension rather than the ones with over dimensions in the existing literature. In comparison with more popular but a bit stronger input‐to‐state stable or input‐to‐state practically stable requirement, only bounded‐input bounded‐state stable requirement is imposed on the dynamics uncertainties, which affect the systems in a persistent intensity rather than in a decaying one. In this paper, to compensate multiple serious system uncertainties and realize global output‐feedback stabilization, a design scheme via switching logic together with varying dimensional filter is developed. In this scheme, 2 switching sequences, which separately generate the gains of the controller and act as the varying dimensions of the filter, are designed to overcome unknown control direction, dynamics uncertainties and nonparametric uncertain nonlinearities, and unknown relative degree, respectively. A 2‐mass lumped‐parameter structure is provided to show the effectiveness of the proposed method in this paper. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic event-triggered composite anti-disturbance and fault-tolerant tracking problem of ships with external ocean disturbances and actuator fault effects. The dynamic event-triggered composite anti-disturbance and fault-disturbance tracking is achieved by combining the disturbance observer and the fault observer with the dynamic event-triggering and the vectorial backstepping control method. The nonlinear disturbance observer is constructed to obtain the online external disturbance estimations in the ocean time-varying environment and thus overcome the unexpected disturbances. The actuator fault observer is exploited to achieve the online fault estimations of actuator faults. The dynamic event-triggered mechanism reduces execution frequencies of control signals to mitigate the tear and wear of ship actuators. The dynamic event-triggered composite disturbance compensation fault-tolerant control ensures the globally uniformly ultimately stability of tracking control system and enables the ship to track the expected trajectory with the small errors. Simulations and comparisons with static event-triggered control on a full-scaled ship validate the dynamic event-triggered control. • Simultaneously addressing time-varying disturbances and actuator faults with observers. • The actuator faults generated by thruster dynamics are included in the composite control. • The dynamic event-triggering with filtering signals mitigate the tear and wear of actuators. [ABSTRACT FROM AUTHOR]