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This paper delves into the output feedback control of systems with dual multi‐memoryless channels, where the data packets transmitted from the sensor to the controller (S/C) and from the controller to the actuator (C/A) are suffered from two different multi‐parallel Markovian fading channels. Two new multi‐state Markovian chains are introduced, by which the multiple fading channels system is transformed into a new jumping parameter system. Then a stochastic maximum principle is given along with an optimal state feedback controller for the case that the state is known. When the state is unknown, a Markov jump linear estimator is designed by using the completing square method. In this case, an output feedback controller is obtained by substituting the real system state with its estimation. Meanwhile, the separation principle is shown. Finally, the validity of these methods is verified by simulation examples. [ABSTRACT FROM AUTHOR]

This paper focuses on the optimal output‐feedback control and stabilization of a networked control system, where both time delay and packet loss are involved. Different from most previous work, the packet loss is Markovian, and the time delay occurs between the actuator and controller. The difficulty is rooted in the failure of the separation principle. The main tools are solving the delayed forward‐backward stochastic difference equations (D‐FBSDEs) and convergent analysis. Resorting to solving D‐FBSDEs and completing the square, we acquire the analytical solution, including the necessary and sufficient solvability condition and the explicit controller, of the finite‐horizon optimal control problem. Based on the finite‐horizon result and convergent analysis, we then obtain the analytical solution of the infinite‐horizon optimal control and stabilization problems. In addition, by analyzing the convergence of the optimal estimator, we establish a constraint relationship between the packet loss probability q$$ q $$ and the system matrix A$$ A $$. The results are evaluated by numerical examples. [ABSTRACT FROM AUTHOR]

This article addresses the problem of designing an event‐triggered fault detector within a networked nonlinear system described by a Takagi–Sugeno (T–S) fuzzy model, accounting for time‐varying delays and denial‐of‐service (DoS) attacks characterized by a binary Markov chain. Our focus is on constructing an event‐triggered residual system, which aims to detect malfunctions in the original fuzzy system while optimizing communication resource allocation. Specifically, it is tailored to combat DoS attacks in the event generator‐to‐fault detector channel and mitigate network‐induced time‐varying delays. Utilizing the Lyapunov–Krasovskii function approach, we formulate linear matrix inequalities to establish the necessary conditions ensuring the asymptotic mean‐square stability of the residual system, meeting a predefined H∞$$ {H}_{\infty } $$ performance criterion. Finally, the simulation results are presented to validate the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

This article addresses the problem of model predictive control of networked jump systems in the presence of DoS attacks and time delays. In the structural framework of the network predictive control system, we mathematically model the networked jump system by using Markov chains to describe the time delays and a polytope model to describe the jump system phenomenon, considering the properties of DoS attacks and time delays. Based on this, we propose a strategy to lessen the effect of network constraints on the control performance of the system. This strategy involves the corresponding control inputs from the control sequence for real‐time active compensation. It includes adjusting the control sequence application length variation based on the duration of the DoS attacks and time delays at each moment. In addition, we demonstrate the recursive feasibility of the control strategy and the global asymptotic stability of the control system from a theoretical perspective through the Lyapunov stability theory. Finally, the effectiveness of the proposed strategy is verified by simulation arithmetic. [ABSTRACT FROM AUTHOR]

The purpose of this article is to develop the receding horizon (RH) estimation for multi‐rate sampled systems with measurement delays and packet losses in the measurements. An event‐triggered transmission scheme is introduced to remove measurements that are unnecessary for the design of the estimator. The stochastic diagonal matrixes are introduced to represent the phenomenon of packet losses, where each component is subject to an individual Bernoulli process. The original system is firstly transformed into a delay‐free one by using the reorganized observation method. Further, a batch form and an iterative form of RH estimation are proposed by minimizing a given cost function that includes some terminal weighting terms based on the new system. The stability of the proposed RH estimation is guaranteed by the natural assumptions and a simulation instance is given to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Summary: An adaptive event‐triggered scheme is considered for networked control systems subject to deception and reply cyber attacks. In particular, the adaptive event‐triggered mechanism is used in the closed‐loop controller design to reduce signal transmission and communication burden. The attacker destroys the system's performance by employing deception attacks on sensor‐to‐controller communication channels and replay attacks on controller‐to‐actuator communication channels, respectively. By utilizing the Lyapunov stability approach, the closed‐loop system guarantees mean square stability and ensure security. The adaptive event‐triggered controller gains are presented by solving a set of matrix inequalities. Finally, a simulation result including the model of a batch reactor is presented to demonstrate the efficiency of the methods proposed. [ABSTRACT FROM AUTHOR]

Networked control system (NCS) is widely used in various fields, but the nonlinear of the controlled plants and the limited network bandwidth bring stability issues, which will affect the performance or even instability of the NCS. To address these aforementioned challenges, this paper proposes a novel nonlinear NCS framework, by considering network‐induced delay, adaptive event‐triggered mechanism, state quantization, control input quantization, and external disturbance based on T‐S fuzzy model. Also, based on this framework, we derive an H∞$$ {H}_{\infty } $$ stability criterion for NCS using linear matrix inequality and propose a collaborative design method for event triggers and controllers. Finally, we verify the superiority and effectiveness of the method by giving two numerical examples. [ABSTRACT FROM AUTHOR]

This paper deals with the design problem of networked cascade control systems (NCCSs) with two different event‐triggered mechanisms (ETMs) for the feedback loops. A combination of stochastic denial‐of‐service (DoS) attack and deception attack has been considered for the communication network. To comply with the practical point of view, the primary and the secondary systems have been considered with distinct disturbances. First, the closed‐loop system with state feedback controllers is provided in a unified stochastic delayed system. Then, the Lyapunov–Krasovskii stability theory and stochastic analysis techniques are employed to derive and formulate H∞$$ {\mathcal{H}}_{\infty } $$ control design conditions in terms of linear matrix inequalities (LMIs). Finally, a superheater steam temperature control is utilized to assess the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

This article proposes an event‐triggering mechanism (ETM)‐based security control strategy for an uncertain networked control system (NCS) to cope with jamming attacks on multiple transmission channels. A structure of the system control block for the attacked uncertain NCS is constructed and a virtual system is designed to cope with the mismatched parametric uncertainty and derive both the optimal control gain and the virtual control gain. Under multiple wireless channels jamming attack, an optimal jamming attack strategy that maximizes the attack power from the attacker's point of view is engineered. Furthermore, an ETM‐based control strategy with jamming parameters is designed to ensure the input‐to‐state stability of NCS under uncertainty and jamming attacks. Finally, the numerical simulation results show the effectiveness of the control algorithm in this article. [ABSTRACT FROM AUTHOR]

Summary: A scheduling strategy of variable sampling period combined with deadband feedback for networked control system is proposed. Variable sampling period algorithm can allocate a reasonable sampling period to each controlled loop according to the network utilization and packet transmission time. Deadband feedback algorithm can alleviate network congestion by appropriately adjusting the packets in the network when the networked control system cannot be scheduled. According to the actual overload and utilization of the network, the designed scheduling strategy dynamically adjusts the sampling period and priority, and improves the performance of the system combined with deadband feedback. Based on the TrueTime platform, the proposed scheduling strategy is verified on a three controlled loops networked control system with interference nodes and limited network resources. The simulation results demonstrate that the designed scheduling strategy can overcome the uncertainty of the upper bound of network resources, improve output control performance, reduce integral absolute error value of the controlled loop, and shorten the packet transmission time. The overall control performance of the system is improved. The designed scheduling strategy is effective. [ABSTRACT FROM AUTHOR]

Summary: This paper is concerned with the distributed secure balancing control problem for battery energy storage systems (BESSs) in a Direct Current (DC) microgrid. The Denial‐of‐service (DoS) attacks, which appear in a random way, are taken into account during the data exchange of individual BESS units. By introducing a well‐designed compensation term, an improved distributed consensus algorithm is developed to deal with the state‐of‐charge (SOC) balance issue in the presence of randomly occurring cyber attacks. With the aid of the Lyapunov stability theory, sufficient conditions are established for the networked control system such that the balance of the SOC for each BESS unit is achieved under certain constraints. The effectiveness of the proposed balance scheme is verified by a series of illustrative simulation experiments. [ABSTRACT FROM AUTHOR]

This paper deals with the design problem of multiloop networked control system (NCS) under interchange attack. This is a new type of attack where the transmitted data are swapped between different control loops which can be more destructive than other types of attacks, such as denial‐of‐service (DoS) attack. In this context, multiple sampled‐data control loops are first considered that use a shared communication network for data transmission. Then, the overall closed‐loop systems with the proposed attack are formulated in a unified stochastic delay system. The proposed framework is also applicable to DoS attack. Based on Lyapunov–Krasovskii theory and stochastic analysis techniques, some conditions in terms of linear matrix inequalities (LMIs) are derived for the H∞$$ {\mathcal{H}}_{\infty } $$ control design problem. Finally, two inverted pendula are utilized for simulation to show the effectiveness of the proposed method. Also, the effects of DoS attack and interchange attack are compared. [ABSTRACT FROM AUTHOR]

Summary: This paper studies the networked control systems (NCS) predictive output feedback control issue with random time delay and denial of service (DoS) attacks. The mathematical description of the random DoS attacks and time delays in controller‐to‐actuator (C‐A) and sensor‐to‐controller (S‐C) communication channels is researched based on Markov stochastic theory. Considering the random characteristics of network‐induced attacks and delays, the closed‐loop NCS is modeled as a discrete‐time linear system with Markov DoS attack and time delay. The stochastic stability criterion of a class of networked predictive control systems with random attack and delay is proposed based on Lyapunov stability theory and the predictive compensation control method. The networked model predictive output feedback controller is designed by applying the parameter compensation method and linear matrix inequality (LMI) technique. Numerical simulation results are proposed to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

This paper presents a novel (SPC) scheme for the path following of autonomous vehicles (AVs) subject to denial of service (DoS) attacks. First, by considering the energy constraints of DoS attacks, bounded but arbitrary packet dropouts is used to characterize the effects of DoS attacks. Then, a switched control system model is established to describe the path following control of AVs under DoS attacks. In what follows, the SPC scheme, which depends on the detection of packet dropout from actuator side, is developed to compensate the packet dropout while there are no feedback measurements available. The main advantage of the proposed SPC scheme is that the predictive control design only depends on the latest available measurement and not affected by external disturbance. This is important to the control of networked systems under DoS attacks. At last, the corresponding experiments on path following control of the AVs are carried out in order to verify the validity of theory results. [ABSTRACT FROM AUTHOR]

This paper addresses the robust finite frequency (FF) H∞ distributed filtering problem for uncertain networked control system (NCS) that consists of heterogeneous subsystems. By using past output measurements and considering the frequency information of disturbance signals, the designed distributed memory filter is able to guarantee that the filtering error system is well‐posed, stable and has the FF H∞ performance. Based on the extended finite frequency bounded realness lemma for uncertain NCSs, the existence condition of robust FF H∞ distributed memory filter is derived. Moreover, it is shown that by taking advantage of more past output measurements of NCS, the proposed design procedure can derive a distributed filter that achieves a lower H∞ performance bound. Finally, a practical example is given to show the effectiveness of the proposed filter design method. [ABSTRACT FROM AUTHOR]

This article concerns the event‐triggered fuzzy filter design for Takagi‐Sugeno (T‐S) fuzzy systems subject to deception attacks under the stochastic multiple time‐varying delays. A sequence of random variables, which are mutually independent but obey the Bernoulli distribution, is introduced to account for the randomly occurring communication delays. In order to efficiently utilize limited network communication bandwidth resources, the event‐triggering scheme is adopted. A fuzzy filter with the attacked input signal is presented. Moreover, due to communication delays caused by event‐triggering schemes and transmission, the filter adopts non‐synchronous premise variables with the system. Then, by utilizing a model transformation technique, the fuzzy systems are developed. Furthermore, using the piecewise Lyapunov functional method technique, the resulting criterion provides sufficient conditions to ensure that fuzzy systems under deception attacks are stochastically stable with an H∞ performance. Accordingly, the conditions for the co‐design of the fuzzy filter and event‐triggering schemes are given. Finally, numerical simulation with the industrial process provided to verify the proposed event‐triggered design. [ABSTRACT FROM AUTHOR]

This study addresses anobserver‐based model predictive control (MPC) algorithm for a networked control system (NCS) under denial of service (DoS) attacks and actuator saturation via an interval type‐2 Takagi–Sugeno (IT2 T–S) fuzzy model. With few studies undertaking the cyber security problems in the research of MPC algorithm, this study considers the data transmission problem when DoS attacks occur. Under DoS attacks, signals in the communication networks will be interfered. The probability of error‐free packet reception depends on signal‐to‐interference‐plus‐noise ratio of the wireless transmission networks. In order to reduce the on‐line computation, an off‐line fuzzy observer is devised to estimate the system states. Meanwhile, an on‐line MPC algorithm is proposed to minimise the performance objective function and obtain the secure model predictive controller gain. Besides, the recursive feasibility is ensured by refreshing the bound of estimation error. Finally, illustrative examples certificate the effectiveness of the presented method. [ABSTRACT FROM AUTHOR]

This paper mainly focuses on the optimal control and stabilization for networked control systems with packet dropout, measurement delay and input delay. The main contributions are two‐fold. Firstly, a necessary and sufficient condition for the finite horizon optimal control problem is obtained. Secondly, a necessary and sufficient condition for the stabilization problem is developed. Moreover, it has been proved that under standard assumptions the stabilizing condition depends merely on the eigenvalue of the system matrix and the probability of packet dropout which is irrelevant to measurement delay and input delay. [ABSTRACT FROM AUTHOR]

Summary: This work is concerned with the robust model predictive control (MPC) for a class of distributed networked control systems (NCSs), in which the input quantization and switching topology are both considered. By utilizing the sector bound approach, the NCSs with quantization are converted into the linear systems with sector bound uncertainties. The topology switching is governed by a switching signal and the dynamic behavior is modeled as a switched control system. A new robust MPC design technique is derived to minimize the upper bound of a weighted quadratic performance index. Moreover, the conditions of both the recursive feasibility of the MPC design and the stability of the resulting closed‐loop system are developed. Finally, simulation results are presented to verify the effectiveness of the proposed MPC design. [ABSTRACT FROM AUTHOR]

Summary: In this paper, stability of a networked control system under denial‐of‐service and false data injection attacks is analyzed with a predictive control method. To model denial‐of‐service attacks on the forward channel of networked control system, game theory is introduced for obtaining balanced results by denial‐of‐service frequency and duration. Then, measurement outputs of the networked control system are maliciously modified in the feedback channel. Under this double attack strategy, the stability of networked control system with predictive control is analyzed using a switched system method. By comparing three types of attack models, advantages of the double attacks are discussed to illustrate the necessity of this research. A numerical simulation is given to demonstrate effectiveness of the proposed methods on a networked control system under double attacks. [ABSTRACT FROM AUTHOR]

Summary: This paper is focused on reliable controller design for a composite‐driven scheme of networked control systems via Takagi‐Sugeno fuzzy model with probabilistic actuator fault under time‐varying delay. The proposed scheme is distinguished from the other schemes as mentioned in this paper. Aims of this article are to solve the control problem by considering the H∞, dissipative, and L2−L∞ constraints in a unified way. Firstly, to improve the efficient utilization of bandwidth, the adaptive composite‐driven scheme is introduced. In such a scenario, the channel transmission mechanism can be adjusted between adaptive event‐triggered generator scheme and time‐driven scheme. In this study, the threshold is dependent on a new adaptive law, which can be obtained online rather than a predefined constant. With a constant threshold, it is difficult to get the variation of the system. Secondly, a novel fuzzy Lyapunov‐Krasovskii functional is constructed to design the fuzzy controller, and delay‐dependent conditions for stability and performance analysis of the control system are obtained. Then, LMI‐based conditions for the existence of the desired fuzzy controller are presented. Finally, an inverted pendulum that is controlled through the channel is provided to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

A classification‐based control approach is proposed for wireless networked control systems with lossy multipacket transmission. This approach takes advantage of a state reconstruction process to deal with the distinct feature of partial failure of data transmission caused by multipacket transmission, and then classifies the difference of the latest received system states and reconstructed ones to design a classification‐based controller. The closed‐loop stability of the system is proven using the switched systems theory. By considering more communication characteristics of multipacket transmission, the proposed approach is shown to give rise to a better system performance by a numerical example. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Summary: This paper examines a codesign problem in industrial networked control systems (NCS) whereby physical systems are controlled over wireless fading channels. The considered wireless channels are assumed to be stochastically dependent on the physical states of moving machineries in the industrial working space. In this paper, the moving machineries are modeled as Markov decision processes whereas the characteristics of the correlated fading channels are modeled as a binary random process whose probability measure depends on both the physical states of moving machineries and the transmission power of communication channels. Under such a state‐dependent fading channel model, sufficient conditions to ensure the stochastic safety of the NCS are first derived. Using the derived safety conditions, a codesign problem is then formulated as a constrained joint optimization problem that seeks for optimal control and transmission power policies which simultaneously minimize an infinite time cost on both communication resource and control effort. This paper shows that such optimal policies can be obtained in a computationally efficient manner using convex programming methods. Simulation results of an autonomous forklift truck and a networked DC motor system are presented to illustrate the advantage and efficacy of the proposed codesign framework for industrial NCS. [ABSTRACT FROM AUTHOR]

Summary: This paper examines the problem of codesigning a robust L2‐gain networked control system along with the network's properties such as sampling interval, service rate, and packet dropout. On the basis of the generalized integral inequality of Bessel‐Legendre inequality approach, sufficient conditions for the existence of a robust L2‐gain controller that incorporates the network's properties are derived and expressed in terms of linear matrix inequalities. Finally, two examples are used to illustrate the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

This study addresses the sliding mode controller design for a networked control system with quantisation and random packet loss. A logarithmic quantiser is adopted in order to guarantee the coarsest density and decrease the possibility of unsuccessful transmission. The quantisation process is designed as an event driven to reduce the amount of data to be transmitted over the channel. A sliding mode controller is adopted to suppress the measurement noise and error caused by the features of a wireless communication channel. The existence of quasi‐sliding mode in the sense of mean‐square and closed loop stability in the sense of mean square are claimed. Simulations are carried out to support the algorithms proposed. [ABSTRACT FROM AUTHOR]

This paper investigates networked control of a collection of battery-powered systems with seriously limited communication capacity and power resources. We aim to stabilize the systems by effectively assigning the communication channels and appropriately allocating the transmission powers so that the energy consumption is within an energy budget. The role of channel assignment is to guarantee network access for all plants when needed; the mission of power allocation is to ensure a desired rate of successful packet transmission for each channel. These two aspects are achieved by a scheduling policy and a power allocation method, respectively, each of which is derived based on stability and schedulability requirements. An interesting co-design framework is derived for communication scheduling, transmission power allocation and stabilizing control. The presented methodology can guarantee a desired decay rate and a given energy consumption for each plant. The effectiveness of the results is demonstrated by numerical simulations. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, the multi-tasking optimal control problem is addressed in the delta-domain for a class of networked control systems (NCSs) with external disturbances. A delta-domain model is proposed to describe the NCSs with random packet dropouts and long-time delay, and the so-called ε-Nash equilibrium is employed to quantify the impacts from the disturbances on the underlying NCSs. The multi-tasking optimal control strategies are developed and the upper bound for the ε-Nash equilibrium is provided explicitly. Some simulation results on the two-area load frequency control system are given to show the validity and applicability of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An event‐based state estimation approach for reducing communication in a networked control system is proposed. Multiple distributed sensor agents observe a dynamic process and sporadically transmit their measurements to estimator agents over a shared bus network. Local event‐triggering protocols ensure that data is transmitted only when necessary to meet a desired estimation accuracy. The event‐based design is shown to emulate the performance of a centralised state observer design up to guaranteed bounds, but with reduced communication. The stability results for state estimation are extended to the distributed control system that results when the local estimates are used for feedback control. Results from numerical simulations and hardware experiments illustrate the effectiveness of the proposed approach in reducing network communication. [ABSTRACT FROM AUTHOR]

In this paper, a gradient descent method based delay estimator is proposed for use with a variable gain control strategy for networked control systems. The delay estimator is developed in such a way that its boundedness is ensured. The performance of the estimator with variable gain controller is evaluated on a temperature control plant with network in the feedback loop. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the problems of stabilization of networked control systems with quantization and actuator saturation via delta operator approach. The definition of the domain of attraction for delta operator systems is introduced to analyze the stochastic stability of the closed-loop networked control systems. The quantizer is a uniform one with arbitrary quantization regions, and the packet dropout process is modeled as a Bernoulli process. On the basis of the zoom strategy and Lyapunov theory in delta domain, sufficient conditions are given for the closed-loop delta operator systems to be mean square stable, and the feedback controllers are designed to ensure the stability of networked control systems. A single link direct joint driven manipulator model is presented to show the effectiveness of the main results. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article is concerned with observer and controller design for networked control systems, where the considered plant refers to a class of discrete-time communication delay Markovian jump systems. In the study, random packet losses and output quantization are considered simultaneously. The packet losses considered here includes sensor to controller and controller to actuator sides, which are modeled as two Bernoulli distributed white sequences, respectively. An observer-based control scheme is developed to stabilize the closed-loop systems. Finally, an illustrative example is provided to show the applicability of the proposed control method. © 2016 Wiley Periodicals, Inc. Complexity 21: 623-634, 2016 [ABSTRACT FROM AUTHOR]

The problem of H∞ output tracking control over networked control systems (NCSs) with communication limits and environmental disturbances is studied in this paper. A wide range of time-varying stochastic problem arising in networked tracking control system is reduced to a standard convex optimization problem involving linear matrix inequalities (LMIs). The closed-loop hybrid NCS is modeled as a Markov jump linear system in which random time delays and packet dropouts are described as two stochastic Markov chains. Gridding approach is introduced to guarantee the finite value of the sequences of transmission delays from sensor to actuator. Sufficient conditions for the stochastic stabilization of the hybrid NCS tracking system are derived by the LMI-based approach through the computation of the optimal H∞ performance. The mode-dependent robust H∞ output tracking controller is obtained by the optimal iteration method. Numerical examples are given to demonstrate the effectiveness of the proposed robust output tracking controller for NCS. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study is concerned with adaptive model‐based event‐triggered control of an uncertain continuous system with external disturbance. The proposed framework incorporates two important control techniques for reducing communication burden and regulating the states of the system online in control network, that is, adaptive model‐based networked control system and event‐triggered control (ETC). An adaptive model of the plant is capable of generalising the zero‐order hold implementation in traditional ETC schemes, while also providing stability thresholds that are robust to model uncertainties. In the adaptive model‐based controller, the authors present an update law to estimate the parameters of the adaptive model at triggered instant. After revisiting the adaptive model property in the context of event‐triggered communication, an event‐triggered condition is proposed using the Lyapunov technique. The stability condition of the proposed approach does not need explicit knowledge of the plant parameters, but are given only in terms of the parameters of the adaptive model and some bounds in the model uncertainties. In addition, lower bound on transmission periods are provided. Meanwhile, L2 stability with respect to external disturbance is examined. A real‐time simulation example is presented to demonstrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

In this research, the optimal estimation for networked control system with multiplicative noises (MN), one‐step random delays and multiple packet dropouts is studied. Both the sensor‐to‐estimator and controller‐to‐actuator channels are affected by MN. The one‐step random delays and packet dropouts are characterised by a series of Bernoulli variables. By state augmentation, the random circumstances in channels are transformed into random parameters, and the optimal estimators are derived utilising projection theory. For systems without MN, random delays or packet dropouts, the corresponding estimators can be derived as particular cases of the proposed algorithm. Then a sufficient existence condition of steady‐state estimators is derived. Some numerical examples are given to validate the proposed estimation algorithms. [ABSTRACT FROM AUTHOR]

This study proposes a novel sampling and control strategy to find a suboptimal sampling period sequence and control input sequence, such that a quadratic cost function of state and control input of a networked control system (NCS) with packet disordering is minimised. First, a discrete‐time system model of the NCS with packet disordering, transmission delay and packet loss in terms of displacement values of packets is put forward. Second, a linear quadratic regulation (LQR) problem of the NCS is formulated, showing that the optimal controller depends on sampling period and quality of services (QoS) of networks. Interactive effects between sampling period and QoS of networks pose a challenge in solving the LQR problem of the NCS. To overcome this difficulty, different from traditional transmission‐delay‐based or packet‐loss‐based sampling scheme, a novel packet‐disordering‐based sampling period selection scheme is proposed. Furthermore, an algorithm is presented to find a suboptimal solution to the LQR problem in this study. Finally, simulation results demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, the problem of H ∞ output tracking control for networked control systems with random time delays and system uncertainties is investigated. Effective sampling instant that is tightly related with transmission delay from sensor to actuator is proposed to ensure that the random variable time delay is always shorter than one effective sampling period. By using both active time-varying sampling period strategy and hybrid node-driven mechanism, the switching instant is coincided with the effective sampling instant. An augmented time-varying networked tracking system model is provided by including the output tracking error as an additional state. However, random transmission delay causes indeterminate sampling period, which induces infinite subsystems. Gridding approach is introduced to transform the continuous time axis into discrete-time sequences, which guarantees the finite number of switching rules. By employing multiple Lyapunov-Krasovskii functions, linear matrix inequality (LMI)-based output tracking H ∞ performance analysis is presented, and robust switching H ∞ model reference tracking controller for networked control systems with communication constraints and system uncertainties is designed to guarantee asymptotic tracking of prescribed reference outputs while rejecting disturbances. Finally, simulation results illustrate the correctness and effectiveness of the proposed approaches. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a new model is proposed to describe networked control systems (NCS) with delays and quantization errors. Firstly, the non-idealizations are unified in the classic robust control framework and the entire system is modeled as a discrete system closed via a block uncertainty. Then, the stability criteria are derived using small gain theorem, μ tool and integral quadratic constraint (IQC) method, respectively. Finally, a simulation and a numerical example are provided to demonstrate the effectiveness of the proposed methods. This work is supported by the Science Foundation of China University of Petroleum, Beijing (No.YJRC-2013-11) and National Natural Science Foundation (NNSF) of China under Grant 61374033. [ABSTRACT FROM AUTHOR]

This article studies the problem of observer-based dissipative control problem for wireless networked control systems (NCSs). The packet loss and time delay in the network are modeled by a set of switches, using that a discrete-time switched system is formulated. First, results for the exponential dissipativity of discrete-time switched system with time-varying delays are proposed by using the average dwell time approach and multiple Lyapunov-Krasovskii function. Then, the results are extended to drive the controller design for considered wireless NCS. The attention is focused on designing an observer-based state feedback controller which ensures that, for all network-induced delay and packet loss, the resulting error system is exponentially stable and strictly [ABSTRACT FROM AUTHOR]

It has been very popular to design a controller to attain multiple objectives in many engineering applications in the past few years. The so-called mixed H2/H∞ control is a typical this kind of case. Generally speaking, the problem of mixed H2/H∞ control is to find a controller not only to minimize the H2 performance (cost function) but also to satisfy the H∞ performance in spite of the worst disturbance, see references [1-6]. To mention one of them, Yang et al. [2] has studied the robust mixed H2/H∞ control problem for a class of uncertain discrete-time nonlinear stochastic systems. The nonlinearities, which are represented by stochastic variables, have been tackled with by a new approach; the uncertainties, which are described as deterministic norm-bounded parameter perturbations, have been dealt with by the celebrated S-procedure. The resulting closed-loop system is exponentially mean square quadratically stable and attains the H2 control performance with a prescribed H1 attenuation level. Hence, from the practical engineering application point of view, the mixed H2/H∞ controller design problem has an obvious physical meaning. In some industrial applications, such as automobiles, manufacturing plants, and aircrafts, system components (the physical plant, the sensor, and the controller) are located at different places, [ABSTRACT FROM AUTHOR]

In this article, the problem of reliable gain-scheduled H∞ performance optimization and controller design for a class of discrete-time networked control system (NCS) is discussed. The main aim of this work is to design a gain-scheduled controller, which consists of not only the constant parameters but also the time-varying parameter such that NCS is asymptotically stable. In particular, the proposed gain-scheduled controller is not only based on fixed gains but also the measured time-varying parameter. Further, the result is extended to obtain a robust reliable gain-scheduled H∞ control by considering both unknown disturbances and linear fractional transformation parametric uncertainties in the system model. By constructing a parameter-dependent Lyapunov-Krasovskii functional, a new set of sufficient conditions are obtained in terms of linear matrix inequalities (LMIs). The existence conditions for controllers are formulated in the form of LMIs, and the controller design is cast into a convex optimization problem subject to LMI constraints. Finally, a numerical example based on a station-keeping satellite system is given to demonstrate the effectiveness and applicability of the proposed reliable control law. © 2014 Wiley Periodicals, Inc. Complexity 21: 214-228, 2015 [ABSTRACT FROM AUTHOR]

The stochastic stability problem of networked control systems (NCSs) with random time delays and packet dropouts is investigated in this paper. The mathematical NCS model is developed as a stochastic discrete-time jump system with combined integrated stochastic parameters characterized by two identically independently distributed processes, which accommodate the abrupt variations of network uncertainties within an integrated frame. The effective instant is introduced to establish the relationship between the destabilizing transmission factors and stability of NCSs. The stabilizing state feedback controller gain that depends not only on the delay modes but also on the dropouts modes is obtained in terms of the linear matrix inequalities formulation via the Schur complement theory. A numerical example is given to demonstrate the effectiveness of the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper is concerned with the fault detection filter (FDF) design for networked control systems subject to time-varying transmission intervals and delays, packet dropouts, and communication constraints. The considered communication constraint is that only one network node is allowed to gain access to the shared communication channel. Also, the accessing of each node is scheduled by a specified stochastic protocol, and the remote FDFs perform the FD task only with these partially available measurements. By focus on the network-induced phenomena, the whole FD system are first modeled in the framework of switched stochastic systems with multiple stochastic parameters. Subsequently, by using the multi-Lyapunov functional approach and novel analysis approach, less conservative conditions including some previous existing results are derived to construct such FDFs. Finally, an example is given to illustrate the effectiveness of the proposed method.Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a methodology for designing an H∞ output feedback controller for discrete-time networked control systems has been considered. More precisely, network-induced delays between the sensor and the controller is modelled by a Markov chain with transition probabilities which are not assumed to be fully known. The systems parameter uncertainties are assumed to be norm-bounded and possibly time-varying. To the best of the authors knowledge, the problem of designing a partially mode delay-dependent H∞ output feedback controller for NCSs with partially known transition probability matrix has not been investigated in the literature. Based on the Lyapunov-Krasovskii functional approach, sufficient conditions for the existence of a robust partially mode delay-dependent H∞ output feedback controller are given in terms of bilinear matrix inequalities which can be solved using a cone complementarity linearization algorithm. The proposed design methodology differs from the existing design methodologies in that dynamic output feedback controllers are parameterized by both modes and transition probabilities, as opposed to the existing design approaches which parameterize controllers by modes only. The results obtained reduce to the existing results on fully known transition matrices when transition probabilities are fully known. It is shown that the proposed methodology can be applied to real world systems. The proposed design methodology is verified by using a DC servo motor system where the plant and the controller are connected via a cellular network with partially known transition probability matrix. [ABSTRACT FROM AUTHOR]

In this paper, stochastic optimal strategy for unknown linear discrete-time system quadratic zero-sum games in input-output form with communication imperfections such as network-induced delays and packet losses, otherwise referred to as networked control system (NCS) zero-sum games, relating to the H8 optimal control problem is solved in a forward-in-time manner. First, the linear discrete-time zero sum state space representation is transformed into a linear NCS in the state space form after incorporating random delays and packet losses and then into the input-output form. Subsequently, the stochastic optimal approach, referred to as adaptive dynamic programming (ADP), is introduced which estimates the cost or value function to solve the infinite horizon optimal regulation of unknown linear NCS quadratic zero-sum games in the presence of communication imperfections. The optimal control and worst case disturbance inputs are derived based on the estimated value function in the absence of state measurements. An update law for tuning the unknown parameters of the value function estimator is derived and Lyapunov theory is used to show that all signals are asymptotically stable (AS) and that the estimated control and disturbance signals converge to optimal control and worst case disturbances, respectively. Simulation results are included to verify the theoretical claims. [ABSTRACT FROM AUTHOR]

The problem of H∞ fault‐tolerant control for networked control systems (NCSs) with actuator failures is addressed in this study. The authors consider the network‐induced delays, including sensor‐to‐controller delay and controller‐to‐actuator delay, to have both an upper bound and a non‐zero lower bound. By using a sampled‐data approach, a new model is formulated based on the updating instants of the ZOH. They derive the criteria which ensure that the sample‐data NCS is stable with H∞ norm γ. The authors design the H∞ fault‐tolerant controller that guarantees the closed‐loop NCS stability with H∞ norm γ, when all control components are operational, as well as when some actuators fail to operate. Simulation examples are given to show the effectiveness and less conservative needs of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a novel event-based control method for nonlinear systems that are input-output linearizable. A method for the design of an event-based state-feedback controller is proposed which approximates the disturbance rejection behavior of a continuous state-feedback system, referred to as reference system, with adjustable accuracy, while simultaneously reducing the feedback communication effort. The event-based control loop is shown to be input-to-state stable. A bound for the deviation between the behavior the event-based control loop and the reference system is derived. This bound is shown to be a function of the event threshold, which is a design parameter that can be freely chosen. Moreover, the deviation between the outputs of both systems is also proven to be bounded and can be made arbitrarily small by appropriately scaling the event threshold. The minimum time in between consecutive events is shown to be bounded from below by some bound which is explicitly determined. The efficiency of the new control method is demonstrated for a bioreactor example. [ABSTRACT FROM AUTHOR]

SUMMARY The fault detection and isolation (FDI) problem with finite frequency specifications is addressed in this paper under the framework of geometric approach for networked control systems subject to communication constraints and packet losses. The considered communication constraint is that only one of the transmission nodes is allowed to gain access to the shared channel. Also, those transmission nodes are scheduled to transmit data according to a specified stochastic protocol. Then by virtues of the common unobservable subspace and the finite frequency stochastic H − index, a novel FDI scheme is developed in which a set of FDI filters that perform the FDI task with only partially available measurements are designed such that each residual is only sensitive to one fault in certain frequency domain and decoupled from the others. Further, less conservative conditions including some previous existing results have been presented to construct the FDI filters. Finally, an example is given to illustrate the effectiveness of the proposed method.Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY This paper is concerned with the design of networked control systems with random network data dropout. It presents a new control scheme, which is termed networked predictive control. This scheme mainly consists of the control prediction generator and network data dropout compensator. Besides, the control prediction generator provides a set of future control predictions to make the closed-loop system achieve the desired control performance, and the network data dropout compensator removes the effects of the network transmission data dropout. Simulation results are presented to illustrate the effectiveness of the control strategy via comparing with other three existing control schemes. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The problem of quantized H∞ control for networked control systems ( NCSs) subject to time-varying delay and multiple packet dropouts is investigated in this paper. Both the control input and the measurement output signals are quantized before being transmitted and the quantized errors are described as sector bound uncertainties. The measurement channel and the control channel packet dropouts are considered simultaneously, and the stochastic variables satisfying Bernoulli random binary distribution are utilized to model the random multiple packet dropouts. Sufficient conditions for the existence of an observer-based controller are established to ensure the exponential mean-square stablility of the closed-loop system and achieve the optimal H∞ disturbance attenuation level. By using a globally convergent algorithm involving convex optimization, the nonconvex feasibility can be solved successfully. Finally, a numerical example is given to illustrate the effectiveness and applicability of the proposed method. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, the problem of guaranteed cost control for networked control systems is addressed by using delta operator Kalman filter approach. To cope with network-induced delays and packet dropout, we take into account the quality-of-service of networks. The networked control system is described as a kind of delayed Markovian jump delta operator systems. Sufficient conditions for the solvability of underlying problem are derived in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness of the developed techniques. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]