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This article realizes an adaptive finite‐time sampled‐data output‐feedback stabilization for a class of fractional‐order nonlinear systems with unmodeled dynamics and unavailable states. K‐filters are constructed to estimate unavailable states, a dynamic signal is introduced to handle unmodeled dynamics and neural networks were used to approximate uncertain nonlinearities existed in stabilizer construction. With the help of backstepping technique, an adaptive sampled‐data output‐feedback stabilizer is exported, and such stabilizer with allowable design parameters and sampling period can render the corresponding closed‐loop system reaches practically finite‐time stable, which can be demonstrated by means of selected Lyapunov function candidates. In the end, two simulations with a numerical and an engineering examples are presented to verify the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This article considers a finite‐time sampled‐data output feedback stabilization problem for a class of feed‐forward non‐holonomic systems. Due to that the states of the focused system are unavailable, a reduced‐order observer is designed to estimate the unavailable states with the sampled output detection of the non‐holonomic system, and two finite‐time sampled‐data stabilizers are respectively constructed by combining the backstepping and adding a power integral techniques. Based on the stepped and switching control strategies, the corresponding closed‐loop system can be globally finite‐time stable by the constructed stabilizers with allowable design constants and sampling period, and this can be proved by choosing an appropriate Lyapunov function candidate. In the end, two simulation examples, which include a numerical and a practical examples, are provided to verify the effectiveness of the proposed finite‐time stabilization method. [ABSTRACT FROM AUTHOR]

The contribution of this investigation lies in solving a sampled‐data output feedback stabilization problem for a class of upper‐triangular stochastic nonlinear systems in p$$ p $$‐normal structure with unavailable states and uncertain time‐varying input delay. A reduced‐order observer with the available sampled output detection is developed for the focused system to estimate its unavailable states, and under such observer, a sampled‐data output feedback stabilizer is constructed by combining the backstepping and adding a power integral techniques. Through selecting the appropriate Lyapunov–Krasovskii functionals, we can demonstrate that the adverse influences caused by the uncertain time‐varying delays in the resulting closed‐loop system can be restricted effectively by the constructed stabilizer, and further, by following the stochastic differential theories, the global stability of the considered resulting closed‐loop system can be analyzed under the suitable design parameters and allowable sampling period. Finally, two examples are given to verify the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

This article focuses on the sampled‐data output feedback stabilization for a class of upper‐triangular nonlinear systems with input delay and p$$ p $$‐normal structure, a reduced‐order observer with the detected sampled output measurement is constructed to evaluate the unavailable states of the considered system, and the backstepping method with adding a power integral technique are adopted to construct the sampled‐data output feedback stabilizer. By selecting a suitable Lyapunov–Krasovskii functional, we can demonstrate that the adverse effects caused by the uncertain input delay can be effectively constrained, and the resulting closed‐loop system with appropriate design constants and allowable sampling period can reach globally stable. Finally, two simulation examples are provided to demonstrate the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

This investigation focuses on the sampled‐data output feedback consensus problem for a class of second‐order nonlinear multi‐agent systems with uncertain time‐varying control coefficient and input unmodeled dynamics. In the considered multi‐agent system, the nonlinearities are more stronger than those under the Lipschitz condition, and the existence of the uncertain time‐varying control coefficient causes the invalidation of the full‐order observer. Under such situation, the reduced‐order observers are designed, and the filters are introduced to handle the uncertainties of the input unmodeled dynamics. By adopting the backstepping method, the sampled‐data consensus protocols are developed, and by selecting an appropriate Lyapunov function candidate, we can demonstrate that the practical leader‐following consensus can be achieved for the considered multi‐agent system by the developed protocols with the suitable design constants and an allowable sampling period. Finally, the effectiveness of the proposed consensus method is illustrated by two simulation examples. [ABSTRACT FROM AUTHOR]

This article devotes a practical finite‐time sampled‐data output consensus investigation for a class of nonlinear multiagent systems with unavailable velocities and undirected topology via output feedback. Noticing that the focused multiagent system features nonlinearities with non‐Lipschitz restriction, and the outputs of the agents are detectable only at the sampling instants, a reduced‐order observer with the sampled output measurement is established for each follower to evaluate the unavailable velocity, and the distributed finite‐time sampled‐data consensus protocols, which are constructed by the established reduced‐order observer as well as the sampled output measurement of the agents, are developed by combining the techniques of adding a power integral and backstepping. By selecting a suitable Lyapunov function candidate, we can verify that the developed sampled‐data consensus protocols which work under the allowable sampling period and the appropriate design parameters can solve the considered practical finite‐time output consensus problem. Finally, two simulation examples, include a numerical and an engineering simulations, are provided to reveal the effectiveness and availability of the proposed consensus scheme. [ABSTRACT FROM AUTHOR]

Summary: This paper investigates a global sampled‐data output feedback stabilization problem for a class of switched stochastic nonlinear systems whose output and system mode are available only at the sampling instants. An observer is designed to estimate the unmeasurable state and thus a sampled‐data controller is constructed with the sampled estimated state. As a distinctive feature, a merging virtual switching signal is introduced to describe the asynchronous switching generated by detecting the system mode via a sampler. By choosing an appropriate piecewise Lyapunov function, it is proved that the proposed sampled‐data controller with allowable sampling period can stabilize the considered switched stochastic nonlinear systems under an average dwell‐time condition. Finally, two simulation results are presented to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Summary: This paper investigates the stabilization problem of sampled‐data output feedback for a class of uncertain switched nonlinear systems in nonstrict‐feedback form. An observer is designed to estimate the unmeasured states, and a sampled‐data controller is obtained by discretizing the virtual controller that is constructed via the dynamic surface control method. It is proved that the designed sampled‐data controller can render all states of the resulting closed‐loop system to converge to a neighborhood of the origin for the arbitrary switching signal, and an allowable sampling period is also given. Finally, 2 examples are presented to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]