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In this article, the dynamic output‐feedback H∞ control problem is investigated for discrete‐time state‐delay systems subject to exogenous disturbances and actuator saturations under the round‐robin communication protocol. Using the switched system approach, the Lyapunov–Krasovskii functional and the modified sector condition, sufficient conditions are first obtained under which the closed‐loop systems can achieve some desirable performance indices such as the boundedness, the H∞ performance and the stability in the absence of disturbances. Then, the controller is explicitly characterized by means of the solvability of linear matrix inequalities. For the case without time delays, the corresponding conditions are also presented. Subsequently, the optimization problems about the performance indices are discussed. Finally, the benefit and effectiveness of the proposed results are specifically illustrated via two simulation examples. [ABSTRACT FROM AUTHOR]

Summary: This paper considers the problem of adaptive fuzzy output‐feedback tracking control for a class of switched stochastic nonlinear systems in pure‐feedback form. Unknown nonlinear functions and unmeasurable states are taken into account. Fuzzy logic systems are used to approximate the unknown nonlinear functions, and a fuzzy observer is designed to estimate the immeasurable states. Based on these methods, an adaptive fuzzy output‐feedback control scheme is developed by combining the backstepping recursive design technique and the common Lyapunov function approach. It is shown that all the signals in the closed‐loop system are semiglobally uniformly ultimately bounded in mean square in the sense of probability, and the observer errors and tracking errors can be regulated to a small neighborhood of the origin by choosing appropriate parameters. Finally, a simulation result is provided to show the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

Summary: This work studies the issue of synchronization control for a type of fractional‐order complex networks, in which the adaptive coupling matrix is considered under the directed topology structure. A pinning control strategy, with the free selection of pinning nodes, is adopted for the synchronization goal. Then, by absorbing the information of eigenvectors and adaptive laws for the coupling matrix, a new Lyapunov function is constructed, by which, and with the assistance of Gronwall inequality and network features, the sufficient condition for Mittag‐Leffler synchronization of the fractional‐order network is established. Accordingly, an easy verifiable algebraic criterion is further derived by means of some matrix inequalities. Besides, we also discuss the effect of outer coupling strength on the achievement of network synchronization. Finally, a numerical experiment is performed to show the evidence of the correctness and effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

This study considers the parameter identification problem of a pseudo‐linear autoregressive moving average system (i.e. linear‐in‐parameter autoregressive output‐error ARMA systems), whose disturbance is an ARMA process. By means of the filtering technique, a filtering‐based gradient iterative (F‐GI) algorithm and a filtering‐based least squares iterative (LSI) algorithms are presented for enhancing the estimation accuracy. Furthermore, a filtering‐based decomposition LSI algorithm is derived for improving the computational efficiency. The key is to use the hierarchical identification principle, to apply the data filtering technique for identification, and to replace the unknown terms in the information vectors with their estimates. Compared with the F‐GI algorithm, the filtering‐based LSI algorithm and the filtering‐based decomposition LSI algorithm have faster convergence rates. The simulation results indicate that the proposed algorithms are effective. [ABSTRACT FROM AUTHOR]

Using the approach of semi‐tensor product of matrices, this study studies a class of event‐triggered control for finite evolutionary networked games, where the control only works at some certain individual states. First, by identifying 'control does not work' as a new specific control strategy, the controlled game dynamics is converted into an algebraic form. Second, to make the game converge globally, two necessary and sufficient conditions for the existence of event‐triggered control are obtained. Meanwhile, a constructive procedure is proposed to design state feedback control strategy and an adjustment method is presented to minimise the control times. Finally, the developed theory results are illustrated by a numerical method. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic event‐based recursive filtering problem is studied for multirate systems over sensor networks. The state update rate of the plant and the sampling rate of the sensors are allowed to be different in order to reflect the multirate sampling strategy. Moreover, the phenomenon of integral measurements is considered to cater for the real engineering practice. To reduce unnecessary data transmissions, the dynamic event‐based mechanism is implemented in the communication channels among sensor nodes. The purpose of this paper is to design a distributed recursive filtering scheme such that, under the influence of the integral measurements, the multi‐rate sampling, and the dynamic event‐based mechanism, there exists a minimal upper bound on the filtering error covariance. An upper bound on the filtering error covariance is first derived by solving a matrix Riccati equation, and then minimized at each sampling instant by choosing appropriate filter gains. Comprehensive simulations are conducted on a numerical example and a practical example to show the effectiveness and superiority of the proposed dynamic event‐based recursive filtering scheme. [ABSTRACT FROM AUTHOR]

In this article, the Tobit Kalman filtering problem is investigated for a class of discrete time‐varying fractional‐order systems in the presence of measurement censoring and stochastic nonlinearities under the Round‐Robin protocol (RRP). The fractional‐order dynamic model is described by the Grunwald–Letnikov difference equation, and the statistical means are utilized to characterize the stochastic nonlinearities that include state‐dependent stochastic disturbances as a special case. The RRP is employed to decide the transmission sequence of sensors so as to alleviate undesirable data collisions. Under the RRP scheduling, only one sensor is permitted to transmit its measurement over the network at each time instant. In light of the renowned orthogonality projection principle, a protocol‐based fractional Tobit Kalman filter is devised with the fractional dynamics and stochastic nonlinearities elaborately addressed. In the pursuit of the filter design, a couple of new terms appear which are in relation to the RRP, fractional dynamics and stochastic nonlinearities arise, and these terms are adequately handled recursively or off‐line. Simulation results are provided to demonstrate the usefulness of the proposed method. [ABSTRACT FROM AUTHOR]

In this article, the maximum‐correntropy‐based Kalman filtering problem is investigated for a class of linear time‐varying systems in the presence of non‐Gaussian noises and randomly occurring uncertainties (ROUs). The random nature of the parameter uncertainties is characterized by a stochastic variable conforming to the Bernoulli distribution. In order to avoid unnecessary data transmission and reduce consumption of limited communication resource, the event‐triggered mechanism (ETM) is introduced in the sensor‐to‐filter channel to decide whether the data should be transmitted or not. A novel performance index is first proposed to reflect the joint effects from the non‐Gaussian noises, the ETM as well as the ROUs. Under the proposed performance index, an event‐based Kalman filter is then constructed whose gain is calculated based on the maximum correntropy criterion. Finally, the effectiveness of the proposed filtering scheme is verified via a practical target tracking example. [ABSTRACT FROM AUTHOR]

In this article, the design problem of ℓ2–ℓ∞ proportional–integral observer (PIO) is investigated for a class of discrete‐time systems with mixed time‐delays. The mixed time‐delays comprise both the discrete time‐varying delays and infinitely distributed delays. The round–robin protocol (RRP) is employed to schedule the data transmissions from the sensors to the observer so as to mitigate the communication burden and prevent the data collisions. A novel PIO is developed whose observer gain is dependent on the data transmission order as a reflection of the effects induced by the RRP scheduling. By resorting to the token‐dependent Lyapunov functional and the matrix inequality technique, the desired PIO is designed with exponentially stable error dynamics of the state estimation and guaranteed ℓ2–ℓ∞ disturbance attenuation/resistance capacity. Finally, a simulation example is exploited to verify the validity of the proposed observer design method. [ABSTRACT FROM AUTHOR]

This study investigatesthe neural‐network (NN)‐based adaptive decentralised controller design issue for a class of large‐scale non‐linear non‐strict‐feedback interconnected systems with time‐varying asymmetric output constraints and dead‐zone inputs. The existences of the non‐strict‐feedback structure, time‐varying asymmetric output constraints, and dead‐zone inputs lead to the construction of the controller of each subsystem is very difficult. By applying the inherent property of Gaussian functions employed in radical basis function NNs, the non‐strict‐feedback structure is skillfully handled, and the adaptive backstepping method is used to construct the desired controllers of all subsystems. Furthermore, Lyapunov stability analysis shows that all the signals of the closed‐loop system are ultimately bounded, and each subsystem output can converge to an arbitrarily small and predefined time‐varying range with the corresponding constraint is always satisfied by employing a barrier Lyapunov function. Finally, simulation results based on a practical example prove the effectiveness of the proposed design strategy. [ABSTRACT FROM AUTHOR]

Summary: An event‐triggered nonfragile distributed H∞ control problem is considered in this article for a class of uncertain nonlinear networked control systems over sensor networks with random communication packet dropouts and redundant channels. Redundant channel transmission is utilized to model the communication measurement and to improve the reliability and quality of the communication data transmission services. In addition, measurement size reduction technique is applied to reduce the energy consumption. An event based transmission scheme is employed to reduce the network burden and energy consumption during the data communication from the sensor to the estimator. With known conditional probability distribution, the random packet losses are modeled as a Bernoulli distributed white sequences. A new set of sufficient conditions is established by using average dwell time approach to obtain the desired observer‐based distributed nonfragile controller with the H∞ performance requirements. Specifically, the explicit form of an observer‐based feedback parameters can be obtained by solving a set of linear matrix inequalities. Finally, to demonstrate the effectiveness of the proposed observer‐based feedback approach, a numerical example is exploited. [ABSTRACT FROM AUTHOR]

In this study, the boundedness and the input‐to‐state stabilisation problems are investigated for a kind of switched delayed differential systems with exogenous disturbances. To reduce the communication burden, an event‐triggered strategy is adopted in the feedback control loop to stabilise the addressed switched delayed differential systems. The notions of boundedness and input‐to‐state practical stability are employed to characterise the control objectives in the presence of exogenous disturbances, switching signals and event‐triggered schemes. Some upper bounds on the system states are obtained and the Zeno phenomenon is shown to be excluded under the proposed event‐triggered scheme. The gain of the feedback controller, the parameters of the event‐triggering function and the switching signals are jointly designed for the underlying delayed differential systems. At last, a numerical example is exploited to given to demonstrate the effectiveness of the authors' developed control scheme. [ABSTRACT FROM AUTHOR]

In this study, the H∞ filtering problem is studied for a class of discrete networked multi‐rate multi‐sensor systems with randomly occurring sensor saturations under the p ‐persistent carrier sense multiple access (CSMA) protocol. A set of mutually independent Bernoulli distributed white sequences is introduced to characterise the random occurrence of the sensor saturations. The p ‐persistent CSMA protocol is employed to decide which sensor is allowed to transmit its measurement to the filter at a certain time instant. By using the lifting technique, the multi‐rate system is converted to a single‐rate one for convenient analysis. The main purpose of the addressed problem is to design an H∞ filter such that the filtering error dynamics is exponentially mean‐square stable and the H∞ performance requirement is satisfied simultaneously. Sufficient conditions are established on the existence of the desired H∞ filters and the corresponding filter gains are then characterised by resorting to the feasibility of certain matrix inequalities. Finally, a numerical example is given to illustrate the effectiveness of the proposed filtering scheme. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the dynamic self‐triggered output‐feedback control problem is investigated for a class of nonlinear stochastic systems with time delays. To reduce the network resource consumption, the dynamic event‐triggered mechanism is implemented in the sensor‐to‐controller channel. Criteria are first established for the closed‐loop system to be stochastically input‐to‐state stable under the event‐triggered mechanism. Furthermore, sufficient conditions are given under which the closed‐loop system with dynamic event‐triggered mechanism is almost surely stable, and the output‐feedback controller as well as the dynamic event‐triggered mechanism are co‐designed. Moreover, a dynamic self‐triggered mechanism is proposed such that the nonlinear stochastic system with the designed output‐feedback controller is stochastically input‐to‐state stable and the Zeno phenomenon is excluded. Finally, a numerical example is provided to illustrate the effectiveness of proposed dynamic self‐triggered output‐feedback control scheme. [ABSTRACT FROM AUTHOR]

Summary: In this article, the nonfragile H∞ filtering problem is investigated for a class of discrete multirate time‐delayed systems over sensor networks. The probabilistic packet dropout occurs during the information transmissions among the sensor nodes in the sensor network characterized by the Gilbert‐Elliott model. In order to take the multirate sampling into account, the state updating period of the system and the sampling period of the sensors are allowed to be different. The variation of the filter gain is considered to reflect the physical errors with the filter implementation. The aim of this article is to design a set of nonfragile filters such that, in the presence of multirate sampling, time‐delays, and packet dropouts, the filtering error dynamics is exponentially mean‐square stable and also satisfies the H∞ performance requirement. By using the Lyapunov‐Krasovskii functional approach, a sufficient condition is derived, which ensures the exponential mean‐square stability and the H∞ performance requirement of the filtering error dynamics. Then, the filter gains are characterized in terms of the solution to a set of matrix inequalities. Finally, a simulation example is provided to demonstrate the effectiveness of the proposed filtering scheme. [ABSTRACT FROM AUTHOR]

Summary: This paper is concerned with the distributed filtering problem for a class of nonlinear time‐delay system over sensor networks subject to multiplicative link noises and switching topology. Both discrete and distributed time delays are included in the system model. Each sensor estimates the system state by means of the measurements not only from itself but also from its neighboring nodes according to an interactive topology. The multiplicative stochastic link noises are taken into consideration to reflect the random perturbations during the information exchanges between sensor nodes. The considered communication topology is switching according to certain predetermined rules. The purpose of the addressed problem is to develop a distributed filtering strategy such that, in the presence of multiplicative stochastic link noises and switching topology, the resulting filtering error dynamics is exponentially stable in the mean square sense and also satisfies the prespecified weighted disturbance attenuation level. In light of the average dwell time technique in combination with stochastic analysis, sufficient conditions are derived for the solvability of the addressed distributed filtering problem, and the desired filtering gains are then obtained through solving certain convex optimization problems. An illustrative simulation example is presented to demonstrate the correctness and applicability of the obtained theoretical results. [ABSTRACT FROM AUTHOR]

This study addresses the observability of Boolean networks (BNs), using semi‐tensor product (STP) of matrices. First, unobservable states can be divided into two types, and the first type of unobservable states can be easily determined by blocking idea. Second, it is found that all states reaching to observable states are observable. Based on subgraph of transition matrix and blocking idea, the second type of unobservable states can be also determined. Approaches are obtained to directly determine some observable or unobservable states. An algorithm is designed for determining the observability of BNs as well. Examples are given to illustrate the effectiveness of the given results. [ABSTRACT FROM AUTHOR]

Summary: This paper deals with the filtering problem for a class of discrete‐time state‐saturated systems subject to randomly occurring nonlinearities and missing measurements. A set of mutually independent Bernoulli random variables is used to describe the random occurrence of the missing measurements. Due to the simultaneous consideration of the state saturation, the randomly occurring nonlinearities, and the missing measurements, it is extremely hard to calculate the actual filtering error covariance in a closed form. As such, the objective of this paper is to construct an upper bound for the filtering error covariance and then design the filter parameters to minimize such an upper bound. The performance of the proposed filters is analyzed in terms of boundedness and monotonicity. Specially, we have shown that the minimum upper bound is always bounded under a mild assumption. Moreover, the relationship between the estimator performance and the arrival probability of the measurements is discussed. A numerical simulation is used to demonstrate the effectiveness of the filtering method. [ABSTRACT FROM AUTHOR]

This paper studies the output tracking problem of Boolean control networks (BCNs) with impulsive effects via the algebraic state‐space representation approach. The dynamics of BCNs with impulsive effects is converted to an algebraic form. Based on the algebraic form, some necessary and sufficient conditions are presented for the feedback output tracking control of BCNs with impulsive effects. These conditions contain constant reference signal case and time‐varying reference signal case. The study of an illustrative example shows that the obtained new results are effective. [ABSTRACT FROM AUTHOR]

This paper is concerned with the sampled-data consensus problem for a class of nonlinear multiagent systems subject to cyber attacks. The considered attacks are assumed to be recoverable, which destroy the connectivity of the network topology with directed spanning tree. In light of the designed sampled-data control protocol, a more general switched system is proposed to model both the cyber attacks and the sampled-data mechanism within a unified framework. Then, by using the contradiction methods, the solution of a class of differential equations is provided to deal with the technical challenge resulting from the switching and sampling issues. Furthermore, in terms of such a solution combined with the constructed piecewise Lyapunov function, sufficient conditions are derived under which the nonlinear multiagent systems subject to attacks achieve the consensus exponentially. The relationship between the attack frequency and the sampling period is also revealed through the obtained conditions. Finally, simulations are given to show the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

ThisIn the system under investigation, the control input is subject to the saturation constraint, and both discrete and distributed time-delays are taken into consideration. The objective of the addressed problem is to design a state feedback controller such that the resulting closed-loop system is asymptotically stable in probability and an upper bound is guaranteed on a prespecified quadratic cost function. Sufficient conditions are established for the existence of the desired guaranteed cost control strategy in terms of the solvability of certain Hamilton-Jacobi inequalities. Simulation results demonstrate the correctness and applicability of the proposed control scheme. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

State estimation problem for power systems has long been a fundamental issue that demands a variety of methodologies depending on the system settings. With the recent introduction of advanced devices of phasor measurement units (PMUs) and dedicated communication networks, the infrastructure of power grids has been greatly improved. Coupled with the infrastructure improvements are three emerging issues for the state estimation problems, namely, the coexistence of both traditional and PMU measurements, the incomplete information resulting from delayed, asynchronous and missing measurements due to communication constraints, and the cyber‐attacks on the communication channels. In this study, the authors aim to survey some recent advances on the state estimation methods which tackle the above three issues in power grids. Traditional state estimation methods applied in power grids are first introduced. Latest results on state estimation with mixed measurements and incomplete measurements are then discussed in great detail. In addition, the techniques developed to ensure the cyber‐security of the state estimation schemes for power grids are highlighted. Finally, some concluding remarks are given and some possible future research directions are pointed out. [ABSTRACT FROM AUTHOR]

This study investigates the sampled-data containment control problem for linear multi-agent systems with multiple leaders under undirected or directed network topology. First, by means of the decomposition method, the containment control problem is transformed into the simultaneous stability analysis issue of certain subsystems. Then, the solution of a class of differential equations, which plays a key role for the addressed problem, is exploited by using the contradiction method. Together with a novel Lyapunov function, sufficient conditions are established to guarantee that all the followers move into the convex hull spanned by the leaders. The proposed results are dependent on the information of the system dynamics, the coupling strength as well as the eigenvalues of topology matrix. Furthermore, the established results are specialised to both the leader--following case and the traditional consensus case. Finally, simulations are given to illustrate the theoretical results derived in this study. [ABSTRACT FROM AUTHOR]

This study investigates the sampled‐data containment control problem for linear multi‐agent systems with multiple leaders under undirected or directed network topology. First, by means of the decomposition method, the containment control problem is transformed into the simultaneous stability analysis issue of certain subsystems. Then, the solution of a class of differential equations, which plays a key role for the addressed problem, is exploited by using the contradiction method. Together with a novel Lyapunov function, sufficient conditions are established to guarantee that all the followers move into the convex hull spanned by the leaders. The proposed results are dependent on the information of the system dynamics, the coupling strength as well as the eigenvalues of topology matrix. Furthermore, the established results are specialised to both the leader–following case and the traditional consensus case. Finally, simulations are given to illustrate the theoretical results derived in this study. [ABSTRACT FROM AUTHOR]

In this paper, the security-guaranteed filtering problem is studied for a class of nonlinear stochastic discrete time-delay systems with randomly occurring sensor saturations (ROSSs) and randomly occurring deception attacks (RODAs). The nonlinearities in systems satisfy the sector-bounded conditions, and the time-varying delays are unknown with given lower and upper bounds. A novel measurement output model is proposed to reflect both the ROSSs and the RODAs. A new definition is put forward on the security level with respect to the noise intensity, the energy bound of the false signals, the energy of the initial system state, and the desired security degree. We aim at designing a filter such that, in the presence of ROSSs and RODAs, the filtering error dynamics achieves the prescribed level of security. By using the stochastic analysis techniques, a sufficient condition is first derived under which the filtering error system is guaranteed to have the desired security level, and then, the filter gain is designed by solving a linear matrix inequality with nonlinear constraints. Finally, a numerical example is provided to demonstrate the feasibility of the proposed filtering scheme. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study is concerned with the event‐based security control problem for a class of discrete‐time stochastic systems with multiplicative noises subject to both randomly occurring denial‐of‐service (DoS) attacks and randomly occurring deception attacks. An event‐triggered mechanism is adopted with hope to reduce the communication burden, where the measurement signal is transmitted only when a certain triggering condition is violated. A novel attack model is proposed to reflect the randomly occurring behaviours of the DoS attacks as well as the deception attacks within a unified framework via two sets of Bernoulli distributed white sequences with known conditional probabilities. A new concept of mean‐square security domain is put forward to quantify the security degree. The authors aim to design an output feedback controller such that the closed‐loop system achieves the desired security. By using the stochastic analysis techniques, some sufficient conditions are established to guarantee the desired security requirement and the control gain is obtained by solving some linear matrix inequalities with non‐linear constraints. A simulation example is utilised to illustrate the usefulness of the proposed controller design scheme. [ABSTRACT FROM AUTHOR]