In this article, the problem of time-varying formation (TVF) tracking for nonlinear multi-agent systems (MASs) is investigated. The agent dynamics are described by one-sided Lipschitz (OSL) and quadratic inner-boundedness (QIB) function. Adaptive continuous TVF tracking protocols for nonlinear MASs are proposed. Compared to prior nonlinear system, this approach is more general and less conservative than nonlinear system with large Lipschitz constant. In addition, the continuous protocols are proposed to avoid undesirable chattering from non-zero inputs of the leader. Finally, the expected theoretical results are achieved through effective numerical simulations.

In this paper, the optimal modified performance problem of multiple-input multiple-output (MIMO) networked control systems (NCSs) with additional interference is investigated, the additional interference includes channel noise, encoding and decoding, quantization, packet dropouts, and bandwidth constraints. Most existing researches focus on the optimal modified performance of NCSs with communication constraints in a single channel or with a single communication constraint in a dual channel. Based on this, and combined with the actual constraints, this paper studies the optimal modified performance of NCSs with multiple communication constraints in a dual channel (forward and feedback channels). By using frequency domain analysis and various decomposition methods, the explicit expression for optimal modified performance under NCSs stability is obtained. The relationship between the optimal modified performance of the NCSs with the internal and external constraints of the NCSs can be observed by the explicit expression of the optimal modified performance. Finally, the accuracy of the obtained conclusions is verified through several sets of numerical simulations.

The stability problem for multiple-input multiple-output (MIMO) networked control systems (NCSs) under external disturbance, packet dropout and channel noise interference is investigated in this paper. External disturbance exists in the forward channel, packet dropout and channel noise interference coexist in the feedback channel and the occurrence of packet dropout is assumed to obey Bernoulli distribution. The stability conditions of the NCSs were obtained through system stability theory, frequency domain method and a variety of decomposition techniques. The results show that the stability of NCSs is affected by the inherent characteristics of NCSs, external disturbance, packet dropout and channel noise. Finally, the effectiveness and superiority of the proposed method is verified by a simulation example.

This brief explores the mixed H-infinity/passive control issue for switched systems in network environment. Considering that system parameters may switch due to various factors, the persistent dwell-time (PDT) switching mode is employed to model this phenomenon. Attackers may insert false data into the system through the information network, thereby disrupting the normal operation of the system. And this behavior is likely to occur probabilistically. The main objective of this article is to establish an efficient dynamic event-triggered mechanism. The core idea of this mechanism is to only perform data transmission tasks when the trigger conditions are not met, thereby reducing unnecessary calculation and resource consumption. By incorporating dynamic variables and applying an exponential decay function, a triggered mechanism is established. Additionally, a mode-dependent non-fragile controller has been devised. This controller has the ability to ensure systems stability in adverse network environments. Lastly, the effectiveness of the proposed control scheme is illustrated via a boost converter circuit.

This study explores the resilience of networked control systems (NCSs) against hybrid attacks, focusing on enhancing their H-infinity performance. To mitigate excessive data transmission, the article introduces dynamic event-triggered schemes and quantizer within the sensor-to-observer communication channel. The network environment is susceptible to various attacks, including denial-of-service (DoS) attacks and deception attacks. An augmented system model is formulated, and through the application of Lyapunov stability theory, conditions for ensuring the asymptotic stability of the system are established. The collaborative design of quantizer parameters, controller gain, and event-triggered thresholds is achieved by solving linear matrix inequalities. Simulation-based theoretical models have effectively demonstrated the reduction of the impact of network intrusions on NCSs, validating the proposed approach.

This study delves into fixed-time and predefined-time bipartite consensus tracking (BCT) of second-order multi-agent systems (MASs), where cooperative and competitive behaviors coexist, while accounting for bounded disturbances. Based on the sliding mode control method, the fixed-time and predefined-time control protocols are proposed to ensure the achievement of fixed-time and prescribed-time BCT for the MASs, which can effectively eliminate singularity and chattering. Leveraging Lyapunov stability, we establish a set of adequate conditions to achieve fixed-time and predefined-time BCT for second-order MASs. Furthermore, we present numerical simulation results to substantiate the theoretical conclusions.

A dynamic event-triggered H-infinity control for networked control systems (NCSs) subject to denial-of-service (DoS) attacks is investigated in this brief. Firstly, the DoS attacks model in communication channel are established based on stochastic variables that obey the Bernoulli distribution, and the attacks rate over network along with switching rules are described. Secondly, the dynamic event-triggered mechanism (DETM) is applied to weaken the influence of DoS attacks and avoid excessive transmission. The threshold parameters under the event-trigger condition can be adjusted by the dynamic characteristics of the systems. Thirdly, by using Lyapunov-Krasovskii functional (LKF) and Linear matrix inequality (LMI) methods, a sufficient condition for NCSs to satisfy the asymptotic stability of given H-infinity is obtained. In addition, a cooperative design scheme of DETM parameters and controller gain is proposed. Finally, a RLC series circuit systems is used as an example to show the effectiveness of the method.

This paper presents a dynamic event-triggered output feedback controller for networked control systems under Markovian deception attacks. A dynamic event-triggered scheme is applied to curtail redundant sensor-to-observer data transfers. Given the prevalence of deception attacks in network signal transmission, these are modeled by a Markov process, and construct an augmented system. Utilizing Lyapunov stability theory, conditions are established for the system's asymptotic stability. Controller gains and event-triggering parameters are derived through the solution of linear matrix inequalities. Simulation results substantiate the controller's effectiveness in countering the impacts of network attacks on the NCSs.

The performance limitation analysis of networked control systems (NCSs) with denial-of-service (DoS) attacks and external disturbances is studied in this paper. An optimal control strategy is proposed to solve the problem of performance limitation, and also an intrusion detection system (IDS) method is used to detect DoS attacks, so that DoS attacks have the least impact on NCSs. A non-cooperative game model between IDS and DoS attackers is established, and the optimal packet delivery rate of NCSs is obtained by solving the Nash equilibrium (NE) strategy of the non-cooperative game. An appropriate Lyapunov function is selected, and the accuracy of the definition is proved by the dynamic programming and mathematical induction. The derived results show that the performance limitation of NCSs is influenced by traditional constraints, DoS attacks, and external disturbances. Finally, some examples are given to show the effectiveness of the obtained theoretical results.

This article is concerned with the optimal tracking performance on linear time-invariant (LTI) discrete-time multi-input–multi-output (MIMO) systems based on quantization, channel noise, and encoding–decoding, as well as bandwidth constraints. Meanwhile, power constraint, feedback and feedforward loops constraints of the systems are also taken into account. The tracking performance expression is described by inner–outer factorization, which is obtained by all stabilizing two-degree-of-freedom compensators. The results will illustrate that tracking performance limitation is decided by nonminimum phase zeros and unstable poles of the given plant. Moreover, time delay, encoding–decoding, channel noise, quantization, and bandwidth constraints also impact the performance. The accuracy of the method is verified by simulation examples.

In this paper, the stability analysis of networked control systems (NCSs) under Denial-of-Service (DoS) attacks is studied. Firstly, the stability analysis for NCSs free of DoS attacks is investigated. Considering the DoS attacks, the game theory is introduced to establish the non-cooperative game between defender and attacker of NCSs. At the same time, the stability of NCSs is analysed in frequency domain, and the signal-to-noise ratio (SNR) expression is given by using spectral decomposition technique and Nash equilibrium (NE) strategy. The packet dropout phenomenon caused by DoS attacks is described by Bernoulli distribution. By virtue of the NE strategy, the stability of NCSs can be optimised. In the obtained results, the influence of the traditional constraints and DoS attacks is illustrated. Finally, some numerical examples are given to show the effectiveness of the derived theoretical results.

The performance analysis about single-input multiple-output networked control systems under quantization and packet dropout is studied in this work. Communication channels are affected by packet dropout and quantization. The optimal tracking performance with quantization and packet dropout is derived by frequency domain method. At the same time, the optimal tracking performance expression is described by a variety of decomposition techniques, which is calculated by the controller that stabilizes the system. The obtained result display that the optimal tracking performance is affected by the internal characteristics of the plant, quantization and packet dropout. Finally, the validity of the theoretical results is verified by numerical examples.

In this paper, the modified performance limitation of multi-input multi-output (MIMO) wireless networked time-delay systems over fading channels is investigated, where the characteristic of the fading channels is assumed to be a random process. The modified tracking performance limitation is considered based on frequency domain representation. The display expressions of performance limitation are achieved by using the co-prime factorization and the spectral decomposition techniques. The obtained results show that the modified performance limitation of the wireless networked time-delay systems is related to the inherent characteristics of the given plant, including the non-minimum phase zeroes, the unstable poles, the encoding-decoding, the fading channels, the bandwidth and the modified factor. Finally, some numerical examples are provided to demonstrate the efficiency of the proposed design method.

This paper presents an optimal tracking performance of multiple-input multiple-output (MIMO) networked control systems (NCSs) with quantization and bandwidth constraints. In this study, we simultaneously consider the encoding-decoding, quantization and bandwidth of communication channel. The optimal tracking performance of NCSs is obtained by spectral factorization technique and partial fraction. The obtained results demonstrate that the optimal tracking performance is influenced by the nonminimum phase zeros and unstable poles as well as their directions for a given plant. In addition, it is shown that characteristics of reference signal, encoding-decoding, quantization, and bandwidth of communication channel are also closely related to tracking performance. Finally, the efficiency of proposed tracking performance is verified by typical examples.

This paper investigates the modified tracking performance limitation of the networked time-delay systems with two-channel constraints. We consider both the white Gaussian noise and packet dropout constraints in the communication channels. In the plant, the non-minimum phase, unstable poles and time-delay are considered. The modified tracking performance limitation expressions will be achieved using the co-prime factorization and the spectral decomposition technique, and the two-parameter controller is adopted. The results show that the modified tracking performance limitation is related to the intrinsic properties of the given plant, including the non-minimum phase zeroes, the unstable poles and the time-delay. Furthermore, the network communication parameters, e.g. the white Gaussian noise, the packet-dropouts probability and the modified factor affect the modified tracking performance limitation of the networked time-delay systems. Finally, some particular examples are provided to illustrate the efficiency of the proposed method.

The optimal modified performance of the multi-input multi-output (MIMO) networked control systems (NCSs) with encoding-decoding, channel noise in the forward channel and packet dropouts, quantization in the feedback channel is investigated in this paper. A new and efficient tracking performance index for the NCSs is presented which prevents variations in the tracking error where there is no integrator in the plant. The optimal modified performance is obtained by the method of coprime factorization and partial fraction. The results demonstrate that the optimal modified performance is related to the locations of the non-minimum phase (NMP) zeros, unstable poles of the given plant as well as their directions. In addition, the modified factor, packet dropouts probability, channel noise and encoding-decoding are also closely related to optimal modified performance of the NCSs. Finally, we present some particular examples to illustrate the theoretical results.