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This paper investigates two classes of synchronization problems of multiple chaotic systems with unknown uncertainties and disturbances by employing sliding mode control. Modified projective synchronization and transmission synchronization are discussed here. For the modified projective synchronization problem, sliding mode controllers are designed to ensure that multiple response systems synchronize with one drive system under the effects of external disturbances. For the transmission synchronization problem, based on adaptive sliding mode control, an integral sliding surface is selected and the adaptive laws are derived to tackle unknown uncertainties and disturbances for such systems. A class of nonlinear adaptive sliding mode controllers is developed to guarantee asymptotical stability of the error systems so that all chaotic systems can synchronize with each other. Simulation results are given to illustrate the effectiveness of the proposed schemes by comparing with the existing methods. [ABSTRACT FROM AUTHOR]

• Considering only a rough boundary of the singularly perturbed parameter κ is available, the bounding ellipsoid obtained this paper is independent on κ such that this ellipsoid can comprise the reachable set of this system for any admissible singularly perturbed parameters. • A κ -dependent LKF is constructed by unequally dividing the delay into two sub-intervals to lead to more superior criteria for the reachable set estimation. • The conditions derived are all independent on the singularly perturbed parameter κ to avoid ill-conditioned numerical trouble. Reachable set estimation problem in allusion to continuous-time singularly perturbed systems that take on time-varying delays and bounded disturbances is discussed in this paper. In many singularly perturbed systems, since the perturbed parameter κ is not available, our task is to determine an ellipsoid as small as possible which can be independent on κ. In this case, for any admissible singularly perturbed parameters, this ellipsoid can surround the states of the system. First, in order to obtain more accurate result, the delay is unequally divided into two sub-intervals and a κ -dependent Lyapunov-Krasocskii functional is established. Then, with the aid of reciprocally convex inequality for each sub-interval, sufficient delay-dependent conditions are established which can make the system states contained by a κ -independent ellipsoid. Finally, a numerical example is given to verify the validity of the result. [ABSTRACT FROM AUTHOR]

• As a first attempt, the SMC problem of PDT switched nonlinear systems is addressed, and the dynamic ET mechanism is introduced to alleviate the limited bandwidth resources, which is more general. • With the dynamic ET mechanism, a new switched SMC law is constructed with the PDT switching strategy that is more general than DT and ADT switching strategies, which can match the subsystem one by one more reasonably and reduce the conservativeness to some extent. • Based on the Lyapunov function approach, some sufficient conditions, which can ensure both the reachability and globally uniform exponential stability with an H ∞ performance of the closed-loop PDT switched system, are derived. In this paper, the H ∞ sliding mode control problem of persistent dwell-time switched nonlinear systems is investigated. Due to the limited bandwidth resources, a dynamic event-triggered mechanism is introduced to alleviate the transmission burden. Considering that the system parameters are switched in accordance with the persistent dwell-time switching strategy, a novel switched sliding mode control law is constructed. Then, drawing on the Lyapunov function approach, sufficient conditions are derived, which not only ensure the reachability of the sliding region around the specified sliding surface but also guarantee the globally uniform exponential stability of the system with an H ∞ performance. Moreover, the specific form of the controller gains is derived by utilizing an efficient decoupling method. Eventually, the validity of the proposed method is validated by two numerical examples. [ABSTRACT FROM AUTHOR]

• A new concept, called fixed-time funnel boundary (FFB), is defined for the first time in this paper. • This work is first to introduce a new control mechanism for TCP/AWM system to ensures that the tracking error satisfies certain transient performances. • The proposed control scheme has the better performance and faster convergent rate than results without FFB or ACT. In this paper, TCP/AWM network congestion control problem is investigated. First, a new funnel boundary (FB) is proposed. And then, in the framework of backstepping, a new control technique is given by virtue of free-will arbitrary time stability and the novel FB, which guarantees that the tracking error converges to the origin within an arbitrary setting time. Besides, the transient performances of the error can also be achieved. Finally, simulation results verify the efficacy and superiority of the presented theoretical findings. [ABSTRACT FROM AUTHOR]

Hopf bifurcation of a delay differential equation modeling two-enterprise interaction mechanism is investigated. For the demands of computer simulation applications, the discrete-time two-enterprise interaction model is proposed by using the forward Euler scheme. By discussing the characteristic equation of linearized part, the local stability criterion of the positive fixed point is presented. Time lag is selected as the bifurcation parameter. Then it is demonstrated that variation of time lag may result in Hopf bifurcation. Furthermore, derivations for the directions and stability of Hopf bifurcation are also given. For the purpose of controlling Hopf bifurcation, a time-delayed feedback control scheme is proposed. Finally, we simulate the main results. [ABSTRACT FROM AUTHOR]

• This is the first work to design a finite-time controller with a new adaptive mechanism by constructing a novel preset region. The dynamical change of the control gain is dependent on the case whether the state trajectories enter or leave a pre-designed domain or not. • The novel adaptive control strategy is presented to avoid the overestimation of the developed adaptive gain based on the adding a power integrator technique and the Lyapunov method. Meanwhile, the novel practical adaptive finite-time controller could improve the dynamic performance of systems and reduce the potential chattering influence. • In practical applications, the system states are usually finite-time stabilized to a neighborhood of the origin, rather than the origin. From this point of view, the investigation of practical finite-time stability (PFTS) for nonlinear systems is more meaningful. In this paper, the PFTS of second-order nonlinear systems has been verified under the developed adaptive finite-time controller. This paper considers the practical adaptive finite-time stabilization problem for a class of second-order systems. Based on the adding a power integrator technique and the adaptive method, a novel adaptive control strategy is presented to assure the trajectories of the closed-loop systems converge to a small neighborhood of the origin in a finite time. Under the adaptive control strategy, the dynamical change of control gain is dependent on the cases whether the state trajectories enter or leave a pre-designed domain or not. In addition, the practical finite-time stability (PFTS) of systems is testified via utilizing the Lyapunov method and adaptive mechanism. Last of all, the validity of the obtained practical adaptive finite-time algorithm is verified via simulation results. [ABSTRACT FROM AUTHOR]

This paper studies the secure synchronization problem for two-time-scale complex dynamical networks with unknown dynamics information and malicious attacks. The challenge is that under complex dynamic networks with unknown dynamic information, all system matrices are unknown. To ameliorate this conundrum, we design a reinforcement learning algorithm, conjoined with a full-order processing of singularly perturbed parameters, with the express objective of securing the stability of the synchronization error system within a context devoid of adversarial intrusions. Second, in order to reduce the impact of malicious attacks, a switching function is developed based on feedback gain. Besides, it is proved that the proposed distributed controllers can still guarantee the convergence of the synchronization error system under malicious attacks. Finally, two numerical examples are given to illustrate the applicability and effectiveness of the proposed algorithm. • A distributed model-free sliding mode controller is presented for SPCDNs. • An iterative algorithm based on RL is employed. • The controller can weaken the influence of the attacks and achieve secure synchronization. [ABSTRACT FROM AUTHOR]

• A novel Lyapunov–Krasovskii functional with a looped-functional is constructed % t k + 1 . • A more general inequality is utilized to process the integral with a derivative of the state variable. • An % H ∞ performance index is raised to deal with the control problem for sMJCDNs. This paper investigates the H ∞ exponential synchronization problem of delayed semi-Markov jump complex dynamical networks by utilizing the sampled-data control scheme. Through introducing a semi-Markov jump model, where the transition rate is related to the sojourn time, the addressed issue is therefore more general. By constructing a suitable Lyapunov–Krasovskii functional with a looped-functional and adopting an advanced inequality method, sufficient conditions for the H ∞ exponential synchronization of delayed semi-Markov jump complex dynamical networks are presented. A numerical example is finally employed to confirm the validity of the proposed method. [ABSTRACT FROM AUTHOR]

• A modified design process of finite-time control (FTC) is achieved by utilizing prescribed performance control (PPC) and pre-assigned finitetime function (PFTF). • The states can converge to a predefined region within the pre-assigned finite-time. • The proposed method is more flexible and simpler since the convergence time is not related with the design parameters and initial values. • Nussubaum gain is employed to tackle the FTC problem for parameter systems with unknown signs. This paper mainly studies an adaptive finite-time control problem for a kind of uncertain strict feedback systems with unknown control gains. First, the original strict-feedback system is transformed into a pure-feedback system. And then, we propose a modified adaptive finite-time design idea on the basis of the property of pre-assigned finite-time function (PFTF) and Nussbaum gain. The designed controller can make sure that all states converge to an arbitrarily region in finite-time and signals in the closed-loop system are finite-time bounded. Moreover, the presented controller is smooth and the settling time does not rely on the initial values and design parameters. Finally, the simulation study is made to illustrate the innovativeness for the proposed scheme. [ABSTRACT FROM AUTHOR]

• The PDTSM, for the first attempt, is considered to describe the variation of the TPs for discrete-time slow sampling MJSPSs. • The impact of uncertain measurement on system performance is studied. • Some sufficient conditions ensuring the FES is MSES under the double-layer switching mechanism, are given. This article concentrates on the extended dissipative filtering for slow sampling singularly perturbed systems based on the double-layer switching mechanism containing the Markov jump signal and the persistent dwell-time switching signal simultaneously. The Markov jumping signal, as the upper layer switching signal, is utilized to describe the jumping of system modes. Then, the persistent dwell-time switching signal is introduced as a lower layer switching signal to characterize the variation for transition probabilities of the Markov chain. Besides, the uncertainties of actual measurement output are assumed to randomly occur, which are described by a set of Bernoulli distributed white sequences. Furthermore, some sufficient conditions ensuring the filtering error system being mean-square exponentially stable with an extended dissipative performance are obtained through the Lyapunov stability theory and some advanced linear matrix transformation techniques. Finally, a simulation example is provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

• As the first attempt, we considered the state information required by the sliding mode controller will be randomly dropouts, which is reflected in the obtained equivalent sliding mode controller. • A novel method is utilized for the SMC problem of the PDT switched systems with data dropouts, and a novel SMC law is proposed. • For the PDT switched systems, some sufficient conditions to guarantee the mean-square exponential stability with data dropouts are derived for the PDT switched systems and the H ∞ performance of the system is analyzed through utilizing the linear matrix inequality technique. This paper concentrates on the sliding mode control problem for a set of discrete-time switched systems. As the first attempt, the persistent dwell-time switching rule is considered in the research of sliding mode control for switched systems. Furthermore, data dropouts are frequently encountered in the process of data transmission, and it should be considered in the process of designing the sliding mode control law so that the state trajectories are guaranteed to move in a region around the specified sliding surface. Based on the Lyapunov theory and the matrix convex optimization technique, the main concern of this paper is to construct a sliding mode controller to ensure that the closed-loop system is mean-square exponentially stable with a prescribed weighted H ∞ performance. Finally, the effectiveness and rationality of the obtained results are verified by a numerical example. [ABSTRACT FROM AUTHOR]

• Compared with the previous works about MJSPSs that the controller was assumed to directly obtain the system mode, we utilize the HMM to describe this asynchronous phenomenon, thus the designed controller is more general and appropriate. • Aiming at the Markov jump and singularly perturbed parameter (SPP) in the system, a proper mode-independent sliding surface and an asynchronous SMC law in consideration of the singularly perturbed parameter matrix are proposed based on the HMM approach. • As the first attempt, the fault-tolerant control scheme is applied in the asynchronous SMC for MJSPSs. Combined with it, the mean-square stability with an acceptable H ∞ system performance is achieved. This work studies the asynchronous fault-tolerant sliding mode control for uncertain stochastic jumping systems subject to singular perturbations, in which the controller is assumed to be able to estimate the hidden system mode through a detector with a conditional probability via the hidden-Markov model. Additionally, in consideration of avoiding the system performance decreases generated by the actuator degradation, the synthesized fault-tolerant sliding mode control scheme is first employed. Through applying a common singularly perturbed parameter based sliding surface, this paper attempts to construct a proper asynchronous sliding mode control law that can ensure not only the reachability but also the closed-loop system is stable with an expected H ∞ performance index. By virtue of the mode-dependent Lyapunov function and the hidden-Markov model approach, sufficient conditions are acquired. Besides, solving linear matrix inequalities for obtaining the control gain matrices are given through the convex optimization theory. Eventually, the effectiveness and feasibility of the proposed asynchronous fault-tolerant sliding mode control scheme are verified by a numerical example. [ABSTRACT FROM AUTHOR]

• The mean square exponential stability of high-order Markovian jump reaction-diffusion. • HNNs (RHNNs) with GUTRs is firstly discussed. • The uncertainties exist in not only parameters but also transition rates. • Each transition rate can be completely unknown or only its estimate value is known. • Our models are more comprehensive and some existing results are special cases of ours. • A numerical example illustrates the validity of our findings. This paper focuses on mean square exponential stability of high-order Markovian jump reaction-diffusion HNNs (RHNNs) with uncertain transition rates (GUTRs) and time-varying delays by Lyapunov-Krasovskii functional method and linear matrix inequality (LMI). In this GUTR model, only part of the transition rates can be known, namely, its estimate error and estimate value are known, but the others have no useful information. Our models are more comprehensive and some existing results are special cases of ours. Finally, a numerical example illustrates the validity of our findings. [ABSTRACT FROM AUTHOR]

• The fuzzy stabilization of CSs is investigated via a sampled-data strategy; • The cost-efficient sampled data controller is designed; • Contrasted with the existing results, our developed one is less conservative. This work focuses on addressing the sampled-data stabilization problem for chaotic nonlinear systems, where the Takagi-Sugeno (T-S) fuzzy model is employed to dispose of the nonlinearity in the system as well as the controller. Contrasted to the traditional control strategy, a more practical piecewise sampled-data controller is developed, where the input delay during the signal transmission is considered. By introducing an approved method for processing fuzzy items and a novel Lyapunov-Krasovskii functional which is inspired by the Wirtinger inequality, as well as an advanced inequality derivation technique, some sufficient conditions with less conservatism are put forward. Appropriate controller gains can be acquired via the solution of the convex optimization problem. At last, the advantages and feasibility of the method proposed are explained by two numerical examples. [ABSTRACT FROM AUTHOR]