The synchronization of delayed neural networks (DNNs) on time scales is discussed via dynamic output feedback (DOF) method. Two types of DOF controllers are designed: (i) Controller related to the dynamic output state; (ii) Controller both related to the dynamic output state and the output error. Under the action of controllers, the slave system is exponentially synchronized to the master system. A generalized Halanay inequality on time scales is presented. By the Lyapunov functional and the proposed Halanay inequality, some synchronization criteria in LMI form regarding to DNNs on time scales are obtained. A numerical example illustrates the validity of the controllers.

This article studies the decentralized impulsive control problem for nonlinear interconnected systems (NISs) based on the dynamic event-triggered mechanism. By the fuzzy logic system (FLS)-based backstepping approach, we first propose a dynamic event-triggered impulsive controller. Unlike traditional event-triggered control (ETC), our impulsive control scheme allows for the instantaneous regulation of system states only at some state-dependent impulse instants, thus avoiding control inputs between two triggering moments. Notably, the resulting closed-loop impulsive systems include hybrid dynamics, general nonlinear characteristics, and prescribed performance constraints simultaneously. Based on the Lyapunov analysis method, we prove that even under discrete impulsive controllers, all closed-loop states remain bounded, and the prescribed tracking performance is achieved, namely, the tracking error can converge to a prescribed bounded region within a desired finite time. Then, the proposed impulsive control approach is further extended to the output-feedback case, under which the impulsive control design is based on the observer states. Finally, we show two simulation examples to validate the effectiveness of impulsive control schemes.

In this article, we investigate the global regulation problem for a class of feedforward nonlinear systems. Notably, the systems under consideration allow unknown input-output-dependent nonlinear growth rates, which has not been considered in existing works. A novel logic-based switching (LBS) gain approach is proposed to counteract the system uncertainties and nonlinearities. The key idea of the proposed approach is that whenever the Lyapunov function does not decrease as desired, the switching mechanism is activated so that a new gain is adopted. Furthermore, a tanh-type speed-regulation function is embedded into the switching mechanism for the first time to improve the convergence speed and transient performance. Then, a switching adaptive output feedback (SAOF) controller, which is of concise form and low complexity, is proposed based on the developed switching mechanism. It is shown that the objective of global regulation is achieved with faster convergence speed and better transient performance under the proposed controller. Moreover, it is also shown that the proposed control approach can be extended with the enhanced switching mechanism to deal with feedforward nonlinear systems with external disturbances. Finally, numerical examples are presented to demonstrate the effectiveness and advantages of our approach in comparison with the existing approaches.

In this article, an observer-based adaptive neural network (NN) event-triggered distributed consensus tracking problem is investigated for nonlinear multiagent systems with quantization. In the first place, the limited capacity of the communication channel between agents is considered. The event-trigger mechanism and dynamic uniform quantizers are set up to reduce information transmission. The next NN is utilized to handle the unknown nonlinear functions. Finally, in order to estimate the unmeasurable states, an NN-based state observer is designed for each agent by using a dynamic gain function. To settle the difficulty caused by the coupling effects of event-triggered conditions and the scaling function in dynamic uniform quantizers and observers, a distributed control protocol with estimated information of its neighbors is designed, which ensures distributed consensus tracking of the nonlinear multiagent systems without incurring the Zeno behavior. The effectiveness of the control protocol is illustrated by a simulation example.

Based on energy-based multiple Lyapunov functions approaches, this article concerns with stabilization and$\mathcal {H}_{\infty }$control for switched uncertain port-controlled Hamiltonian (SUPCH) systems with mode-dependent average dwell time (MDADT) switching. To better deal with the uncertainties of each mode, an improved MDADT scheme along with corresponding constraint conditions is established, and the criterion on globally uniformly asymptotical stability is presented for SUPCH systems in unforced form under the new MDADT mechanism. Subsequently, based on mode-dependent state feedback (MDSF) strategies, the sufficient conditions are derived for stabilization of SUPCH systems. Furthermore, to solve$\mathcal {H}_{\infty }$control problem for SUPCH systems with disturbances, a set of MDSF controllers are constructed, and the$\mathcal {H}_{\infty }$control criterion is obtained by the improved MDADT scheme. Finally, as an application, some simulations on a switched nonlinear RLC circuit system with structural uncertainties are carried out by the proposed control strategies.

In this article, we shall investigate the event-triggered communication control problem for strict-feedback nonlinear systems with measurement outputs. First, two event-triggered communication schemes are designed. Based on both event-triggered schemes, the measurement output and control input signals are only transmitted at triggering time instants, which saves communication costs from the sensor to the controller and from the controller to the actuator. Meanwhile, Zeno behavior can be excluded under the proposed triggering schemes. Second, since the full-state information is not available to the controller, by developing an observer, the system state is estimated and a controller based on estimated state information is designed. Due to the irregular sampling of information communication and state estimation error affects each other, the parameters of the state observer, the controller, and the event-triggering mechanism should be jointly designed. It is proved that the closed-loop system state converges to the origin. Finally, a simulation example verifies the validity of the obtained theoretical result.

This article proposes a dynamic gain approach for investigating the leader-follower consensus problem of nonlinear multiagent systems with both distributed delays and discrete delays. It is assumed that each agent is in the strict-feedback form and satisfies the Lipschitz condition with an unknown constant. A novel dynamic gain observer is first constructed for each follower by only utilizing the output information of the follower and its neighbors. By introducing an observer, a distributed output-feedback control protocol is designed for each follower agent under a directed communication topology. It is proved by the Lyapunov-Razumikhin theorem that the consensus of the multiagent system is achieved with the proposed consensus protocol. Different from the existing results, the dynamic gain is constructed for each follower to propose the consensus protocol, without resorting to the celebrated backstepping technique. Moreover, the time-varying gain is designed in a uniform framework. The effectiveness of the proposed approaches is illustrated by a simulation example.

This article is concerned with the problem of distributed prescribed finite-time observer design for a strictfeedback nonlinear system with external disturbance. The purpose is to reconstruct the unavailable system state based on a group of distributed observers, where each of them can only receive at most 1-D output measurement from the system. First, in the absence of disturbance, a new distributed prescribed finite-time observer featuring time-varying gains is constructed and designed under the assumption of joint observability. It is analytically proved that for any prescribed instant independent of system initial conditions and other design parameters, the obtained distributed observer can guarantee not only the asymptotic convergence to zero of the state error between each observer state and the system state at this prescribed instant but also the definite zero-state error after this prescribed instant. Second, a distributed prescribed finite-time bounded observer is delicately proposed to account for the presence of external disturbance in the system dynamics. It is shown that the state error can be bounded by an arbitrarily positive constant after a prescribed instant. Finally, a numerical example and an electromechanical system are presented to demonstrate the effectiveness of the proposed results.

This article is concerned with the event-triggered output feedback control problem for a class of switched nonlinear strict-feedback systems subject to asymmetric input saturation. The nonlinear terms are assumed to be bounded by a continuous function of the output multiplied by unmeasured states. The hyperbolic tangent function is employed to process the error caused by the event-triggered scheme, and an indicator function of the saturation degree is used to analyze the influence generated by the asymmetric input saturation. By adopting the common Lyapunov function method and the dynamic gain control design approach, a new design procedure based on a reduced-order observer is proposed to construct an output feedback controller. It is proved by the Lyapunov analysis that the proposed event-triggered control scheme can ensure that all the signals of the closed-loop system are globally bounded. Furthermore, the output can be converged to a bounded region around the origin, and this region can be tuned to be small by adjusting the design parameters. Different from typical existing results on the switched nonlinear strict-feedback systems, the celebrated backstepping method is not employed in this article. The continuous stirred tank reactor is finally used to demonstrate the effectiveness of the proposed control scheme.