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The fault-tolerant control problem is investigated for a linear networked system subject to an additive actuator fault as well as random network delays and packet dropouts in the backward and forward channels. To deal with the adverse effects of the actuator fault as well as those communication constraints, an active compensation scheme combining active fault-tolerant control and predictive control is proposed based on the simultaneous estimation of the system state and actuator fault. The obtained closed-loop system is a randomly switched system with bounded round-trip time delays, and the corresponding closed-loop stability condition is derived by using a switched Lyapunov approach. Simulation results for a networked DC motor system are provided to verify the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the control problem of networked nonlinear multiagent systems with communication constraints and unknown dynamics, based on system input–output data. A cost function for the design of networked nonlinear multiagent control systems is presented, which considers not only the coordination performance between agents but also the performance of individual agents. Utilizing a data model to represent discrete-time nonlinear multiagent systems, a networked data-driven predictive control scheme is proposed to optimize control performance, compensate for communication constrains, and achieve both consensus and stability of networked nonlinear multiagent systems. An optimal control protocol is derived, which minimizes the cost function and makes compensation for communication constraints. The criteria of achieving both consensus and stability of networked nonlinear multiagent systems are provided. An example illustrates the performance of the proposed networked data-driven predictive control scheme. [ABSTRACT FROM AUTHOR]

This study concerns the admissible consensus problem for networked singular multi-agent systems with communication delays and agents described by general singular systems. Only the information of outputs is available through the network. An observer-based networked predictive control scheme (NPCS) is employed to compensate for the communication delays actively. Based on NPCS and dynamic compensator (dynamic output feedback), a novel protocol is proposed. Based on graph, algebra and singular system theory, the necessary and sufficient conditions are given to guarantee existence of the proposed protocol. The conditions depend on the topologies of singular multi-agent systems and the structure properties of each agent dynamics. Moreover, a consensus algorithm is provided to design the predictive protocol. A numerical example demonstrates the effectiveness of compensation for networked delays. [ABSTRACT FROM PUBLISHER]

Networked control allows monitoring a plant from a remote location through a communication channel and owns several attractive advantages. One of the major challenges is the control problem of stochastic nonlinear systems with packet losses and/or communication delays. In this paper, the networked control of nonlinear systems with stochastic disturbances in the presence of packet losses is investigated. In order to reduce the effect of data packet losses on the system stability, a model predictive control method is proposed to compensate the packet losses in communication channel. By using stochastic stability theory and a previously designed Lyapunov controller, p th moment practical stability of the networked control system (NCS) is discussed, and a sufficient condition guaranteeing the practical stability of the closed-loop system is provided. Based on the sufficient condition, the relation formula between any prior given control target and the corresponding maximum time of consecutive packet losses is derived, and it is found that the ultimate bound of p th moment is mainly dependent on the maximum time of consecutive packet losses. As an example, networked control of the nonlinear chaotic Lorenz system with stochastic disturbances and data packet losses is considered to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper addresses the design problem of false data injection (FDI) attacks against the output tracking control of networked systems, where the network-induced delays in the feedback and forward channels are considered. The main contributions of this paper are as follows. 1) To actively compensate for the two-channel network-induced delays, a Kalman filter-based networked predictive control scheme is designed for stochastic linear discrete-time systems. 2) From an attacker’s perspective, stealthy FDI attacks are proposed for both the feedback and forward channels so as to disrupt the stability of the resulting closed-loop system while avoiding the detection of a Kalman filter-based attack detector. 3) Both numerical simulations and practical experiments are carried out to show the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

This paper addresses the data-based networked control problem for a class of nonlinear systems. Network communication constraints, such as network-induced delay, packet disorder, and packet dropout in both the feedback and forward channels, are considered and further treated as the round-trip time (RTT) delay that is redefined. By using the packet-based transmission mechanism and the model-free adaptive control algorithm, a data-based networked predictive control method is proposed to actively compensate for the random RTT delay. The proposed method does not require any information on the plant model and depends only on the input and output data of the plant. A simple and explicit sufficient condition, which is related to the upper bound of the RTT delays, is derived for the stability of the closed-loop system. Additionally, a zero steady-state output tracking error can be achieved for a step reference input. The effectiveness of the proposed method is demonstrated via simulation and experimental results. [ABSTRACT FROM PUBLISHER]

This paper discusses the design and practical implementation of solving an external consensus problem for inhomogeneous networked multiagent systems with constant network delay in the output feedback. Based on the recursive equation, a novel prediction strategy is proposed using the transfer function form to overcome the effects of the network delay. By considering a single-input single-output linear system for each agent, the proposed strategy is simulated, demonstrated, and validated through a test-rig application. Concurrently, the stability of the control scheme and the criterion to determine the appropriate coupling gains value for the proposed consensus protocol are also studied. [ABSTRACT FROM PUBLISHER]

The input-to-state stability (ISS) for a class of networked control systems with random delays and packet dropouts appearing simultaneously in both feedback and forward channels is thoroughly investigated in this paper. A new network predictive controller scheme is introduced in order to compensate the effect of transmission delays and packet dropouts. By making use of the small gain theorem, the stability criteria of the considered new system are derived. The proposed stability conditions are fairly easy to check and considerably less conservative than the existing ones. These criteria reveal that, if the original linear systems are controllable and observable, then, by adopting the proposed networked-predictive-control scheme, the ISS properties can be guaranteed for the overall system despite the effects of networking such as transmission bounded delays, packet dropouts, and possible disturbance inputs. When no disturbance inputs occur, the system stability can be guaranteed for random delays with a certain bound or else for any large constant delays. Results for two illustrative examples are given to validate the proposed control scheme, the second one being a laboratory-scale dc-motor rig. [ABSTRACT FROM PUBLISHER]

This paper studies the problem of predictive output feedback control for networked control systems (NCSs) with random communication delays. A networked-predictive-control scheme is employed to compensate for the network-induced delay. Furthermore, the time-varying predictive controller with mixed random delays for networked systems is introduced. Then, the system is formulated as a Markovian jump system. New techniques are presented to deal with the distributed delay in the discrete-time domain. Based on the analysis of closed-loop NCSs, the designed predictive time-varying output feedback controller can guarantee system stability. Simulation example demonstrates the compensation for random communication delays and data loss in networked systems using the proposed predictive scheme. [ABSTRACT FROM PUBLISHER]

Abstract: This paper is concerned with the design, analysis and real-time implementation of networked control systems using the predictive control strategy. The analysis of the characteristics of networked control systems is detailed, which shows that a networked control system is much different from conventional control systems. To achieve the desired performance of closed-loop networked control systems, the networked predictive control scheme is introduced. The design, stability analysis and real-time implementation of networked predictive control systems are studied. It is illustrated by simulations and practical experiments that the networked predictive control scheme can compensate for random network communication delay and data dropout, achieve desired control performance and have good closed-loop stability. [Copyright &y& Elsevier]

The consensus problem of discrete-time networked multi-agent systems (NMASs) with a communication delay is investigated in this article, where the dynamics of agents described by discrete-time linear time-invariant systems can be either uniform or non-uniform. For the NMASs with a directed topology and constant delay, a novel protocol based on the networked predictive control scheme is proposed to compensate for communication delay actively. Using algebraic graph theories and matrix theories, necessary and/or sufficient conditions of achieving consensus are obtained, which indicates that, under the proposed protocol, the consensus is independent of the network delay and only dominated by agents' dynamics and communication topology. Meanwhile, the protocol design and consensus analysis are also presented in the case of no network delay. Simulation results are further presented to demonstrate the effectiveness of theoretical results. [ABSTRACT FROM AUTHOR]

This article is concerned with the problem of H∞ predictive control of networked control system with random network delay. A new control scheme termed networked predictive control is proposed. This scheme mainly consists of the control prediction generator and network delay compensator. While designing the predictor, the control input to the actuator may be different due to networked induced time-delay and data dropout, and two cases are considered depending on the way that the observer obtains the plant control input ut. The necessary and sufficient conditions are given for the closed-loop networked predictive control system to be stochastically stable for different ut and random network delays in controller to actuator channel (CAC) and sensor to controller channel (SCC). A simulation study shows the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This article deals with the problem of L2-gain for a class of networked control systems with time-varying network delay in both forward and feedback channels. An improved network predictive control scheme is proposed to compensate the effects of network delay and data dropout using a switching control strategy. Based on the average dwell time method, the restrictions that the original delay-compensation strategy imposes on the subsystems are relaxed and a sufficient condition for weighted L2-gain is developed for a class of switching signal. An example illustrates the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]