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This article investigates the distributed optimal cooperation problems for multiple high-order systems, in which the dynamics of each agent is allowed to be subject to unknown nonlinearities. To eliminate the effect caused by unknown nonlinearities, a nonlinearity estimator is developed based on agents’ states, which successfully reconstructs the nonlinear dynamics if the unknown nonlinearities are bounded. And to minimize the sum of multiple local nonlinear cost functions with Lipschitz-type gradients, a couple of static and adaptive state-dependent algorithms are designed, respectively, where each agent may only have access to its own local cost function. It is challenging to solve such an optimal cooperation problem as the performance of the whole multiagent network is evaluated by the sum of all local performance functions. In order to fulfill the goal of cooperative optimization, a state-dependent distributed optimal cooperation algorithm is proposed first. By utilizing tools from the Lyapunov stability theory and convex optimization analysis, it is proven that the considered distributed optimal cooperation problem for high-order nonlinear systems can be solved by the proposed optimal cooperation algorithm if the state-dependent parameters are suitably selected. It is noted that the selections of the state-dependent parameters depend on some global information of the multiagent systems. Furthermore, by incorporating the proposed optimal cooperation algorithm with adaptive parameters strategy, the optimal cooperation problem is solved in a fully distributed manner. Finally, a numerical simulation is shown to verify the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

The consensus problems of fractional-order multi-agent systems(FOMAS) are investigated under a fixed interaction graph. A consensus protocol that has current and time-delay states is designed. The conception of practical consensus of FOMAS is proposed. The asymptotical consensus condition is obtained by taking advantage of Laplace transform. Furthermore, the practical consensus condition of the FOMAS with the protocol is given by direct derivation. Through numerical simulation, we find that the standard control protocol can not achieve consensus in some situations. However, the proposed protocol could make the states of multi-agent be consensus or even practical consensus. [ABSTRACT FROM AUTHOR]

In this article, the free-will arbitrary time consensus is formulated for multiagent systems. This consensus protocol is independent of initial conditions and any other system parameters. With such a protocol, the multiagent system is shown to attain consensus as well as average consensus within the prespecified arbitrary time. Agents rendezvous can also be accomplished with the given protocol. Communication imperfections are easily handled with the designed protocol. Robust free-will arbitrary time consensus protocol is also designed. The stability of such nonlinear nonautonomous protocols is established using suitable Lyapunov functions. Simulation examples confirm the theoretical findings. [ABSTRACT FROM AUTHOR]

This article investigates the distributed average tracking (DAT) problem for disturbed second-order multiagent systems, where a crowd of agents is required to track the average of the multiple time-varying signals. First, a new kind of distributed average estimator is developed for each agent to estimate the average of the multiple time-varying signals in finite time. The protocol possesses the distinguished feature of robustness to initialization errors, which can recover from network alterations. Then, an observer-based finite-time tracking protocol is proposed to make each agent exactly track the average of the multiple time-varying signals in finite time in the absence of velocity measurement. By carefully analyzing the dynamic properties of the tracking error system, a suitable Lyapunov function is constructed to estimate the settling time for convergence of the tracking error system theoretically. Furthermore, an adaptive DAT protocol is proposed, which is a fully distributed protocol because it can solve the DAT problem without using any global information. Finally, two simulation examples are provided to verify the effectiveness of the methods. [ABSTRACT FROM AUTHOR]

Distributed stabilization problem is studied in this article for multiple heterogeneous agents in the uncertain strong–weak competition network with exogenous disturbances, where the agents are modeled by the second-order systems with different nonlinear intrinsic dynamics, and the network uncertainty is characterized by unknown nonzero parameters, which contains three different relationships among agents: 1) cooperation; 2) strong competition; and 3) weak competition. To achieve distributed stabilization, the whole network is first divided into two parts: 1) identifiable part and 2) unidentifiable part, and a new distributed robust integral sign of the error (RISE) controller is designed for each agent, where the selection rules of the corresponding parameters are given. It is shown that the heterogeneous multiagent system (MAS) can achieve distributed stabilization no matter whether the identifiable part is structurally balanced or not. Furthermore, it is proved that the global distributed stabilization is achieved for the heterogeneous agents provided that the partial derivatives of the nonlinear intrinsic dynamics are bounded. Finally, two numerical examples are given to demonstrate the effectiveness of the designed controller. [ABSTRACT FROM AUTHOR]

In this article, the global consensus problem of ring-networked nonholonomic systems with a saturated input is considered. Based on the Lyapunov method and appropriate related technologies, the stabilization of the nonholonomic systems is achieved toward consensus. Assuming that each agent has its own position information available in the global coordinates and can obtain the position information of its neighbors, global consensus is achieved asymptotically by using the designed distributed saturated controllers. A wireless local area network is set up with a local computer as the controller, having data transmitted through the wireless network so that the movement of the robots can be controlled. Consistent simulation and experimental results are presented to illustrate the practical design and theoretical analysis. [ABSTRACT FROM AUTHOR]

The group consensus problems of heterogeneous multiagent networks with input time delays are investigated in this paper. In this complex networks, the agents’ dynamics are modeled by the first-order and the second-order multiagent systems, where a novel dynamic group consensus protocol is designed through the competitive relationship among the agents. By using matrix theory and the frequency-domain method, some algebraic criteria are theoretically established for reaching a group consensus in the following two cases: 1) with the identical and 2) different input time delays. Meanwhile, the conservative assumptions existed in the relevant literatures are absolutely relaxed, i.e., the in-degree balance and the geometric multiplicity of zero eigenvalue of Laplacian matrix are at least two. Finally, the effectiveness of our results is illustrated by numerical examples. [ABSTRACT FROM AUTHOR]

This paper focuses on consensus analysis of fractional‐order singular multi‐agent systems (FOSMASs) with uncertainties under fixed topology. The definition of admissible consensus or robust admissible consensus of FOSMASs is proposed and the communication network topology is assumed to be an undirected or a directed graph. Through a coordinate transformation, the admissible consensus of FOSMASs is converted into two parts, one is regularity and impulse‐free of single fractional‐order singular (FOS) linear system, another one is admissibility of multiple FOS linear systems. The consensus conditions are expressed by linear matrix inequalities (LMIs) via SVD technique. Some simulation examples are given to show how to solve LMIs to get the control gain. The simulation results display that the states of the FOSMAS can achieve consensus by using the solved control gain. [ABSTRACT FROM AUTHOR]

Faster convergence is always sought in many applications. Designing fixed-time control has recently gained much attention since, for this type of control structure, the convergence time of the states does not depend on initial conditions, unlike other control methods providing faster convergence. This paper proposes a new distributed algorithm for second-order consensus in multiagent systems by using a full-order fixed-time convergent sliding surface. The stability analysis is performed using the Lyapunov function and bi-homogenous property. Moreover, the proposed control is smooth and free from any singularity. The robustness of the proposed scheme is verified both in the presence of Lipschitz disturbances and uncertainties in the network. The proposed method is compared with a state-of-the-art method to show the effectiveness. [ABSTRACT FROM AUTHOR]

Summary: This paper is focused on the node‐to‐node consensus problem of multiagent systems consisting of general linear node dynamics under directed switching topologies. Specifically, it is assumed that the multiagent systems under consideration have 2 layers, ie, leader layer and follower layer. When uncertainties on the pinning links between the 2 layers exist, the coordination goal is to present some robust control laws, which are distributed such that the states of each follower asymptotically converge to those of its corresponding leader. By using tools from M‐matrix theory and multiple Lyapunov methods, some sufficient criteria are derived to achieve this goal. Finally, 2 simulation examples are performed to validate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This brief studies the fixed-time average tracking problem for multiagent systems under communication constraints, in which each agent has a limited sensing range. A distributed nonlinear control protocol is proposed to make a team of agents track the average of multiple time-varying reference signals with bounded derivatives. Furthermore, the initial interaction patterns can be preserved under the designed protocol and the average tracking can be achieved within fixed time, where the bound of settling time is independent of the initial conditions. Thus, the fixed convergence time can be flexibly adjusted. Finally, some numerical examples are provided to illustrate the performance and effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, the robust fixed-time consensus problem for multiagent systems with nonlinear dynamics and uncertain disturbances under a weighted undirected topology is investigated. Some nonlinear control protocols are proposed under which fixed-time consensus in the considered multiagent systems can be ensured. Compared with the initial-condition based finite-time consensus, it is theoretically shown that any prescribed convergence time for the achievement of consensus can be guaranteed within fixed time regardless of the initial conditions. Furthermore, the achievement of consensus is shown to be robust against bounded uncertain disturbances affecting the agents. Finally, some numerical examples are provided to illustrate the performance and effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper proposes a control framework, called pulse-modulated intermittent control, which unifies impulsive control and sampled control. Specifically, the concept of pulse function is introduced to characterize the control/rest intervals and the amplitude of the control. By choosing some specified functions as the pulse function, the proposed control scheme can be reduced to sampled control or impulsive control. The proposed control framework is applied to consensus problems of multiagent systems. Using discretization approaches and stability theory, several necessary and sufficient conditions are established to ensure the consensus of the controlled system. The results show that consensus depends not only on the network topology, the sampling period and the control gains, but also the pulse function. Moreover, a lower bound of the asymptotic convergence factor is derived as well. For a given pulse function and an undirected graph, an optimal control gain is designed to achieve the fastest convergence. In addition, impulsive control and sampled control are revisited in the proposed control framework. Finally, some numerical examples are given to verify the effectiveness of theoretical results. [ABSTRACT FROM PUBLISHER]

This paper deals with a consensus tracking problem for multiagent systems (MASs) with Lipschitz-type nonlinear dynamics and directed switching topology. Unlike most existing works where the relative full state measurements of neighboring agents are utilized, it is assumed that only the relative output measurements of neighboring agents are available for coordination. To achieve consensus tracking in the considered MASs, a new class of observer-based protocols is proposed. By appropriately constructing some topology-dependent multiple Lyapunov functions, it is theoretically shown that distributed consensus tracking in the closed-loop MASs equipped with the designed protocols can be ensured if each possible topology contains a directed spanning tree rooted at the leader and the dwell time for the switchings among different topology is less than a derived positive quantity. Interestingly, it is found that the communication topology for observers’ states may be independent with that of the feedback signals. The derived results are further extended to the case of directed switching topology with only average dwell time constraints. Finally, the effectiveness of the analytical results is demonstrated via numerical simulations. [ABSTRACT FROM PUBLISHER]

This brief addresses a weak cooperation behavior, i.e., position cohesion and velocity consensus for a class of second-order multiagent systems with mismatch parameters from a viewpoint of power systems. All the agents can possess mismatch parameters and receive only the position information from its neighbors throughout the communication network. Sufficient conditions are established, and the hidden mechanism governing the weak cooperation behavior is elucidated. Simulations are given to illustrate the effectiveness of the derived theoretical results. [ABSTRACT FROM PUBLISHER]

Smart grids are electric networks that employ advanced monitoring, control, and communication technologies to deliver reliable and secure energy supply, enhance operation efficiency for generators and distributors, and provide flexible choices for prosumers. Smart grids are a combination of complex physical network systems and cyber systems that face many technological challenges. In this paper, we will first present an overview of these challenges in the context of cyber–physical systems. We will then outline potential contributions that cyber–physical systems can make to smart grids, as well as the challenges that smart grids present to cyber–physical systems. Finally, implications of current technological advances to smart grids are outlined. [ABSTRACT FROM AUTHOR]

This paper studies the higher order finite-time consensus protocol for heterogeneous multi-agent systems (HMASs). By adding a power integrator method and using heterogeneous domination method, two kinds of consensus protocols are proposed with state feedback and output feedback, respectively. First, for the leaderless and leader-follower HMASs, the continuous finite-time consensus protocols are proposed. Then, by designing a finite-time observer, the output-feedback finite-time consensus protocol is developed. Finally, simulations are performed to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper studies second-order consensus in multi-agent systems with sampled position and velocity data. A distributed linear consensus protocol with second-order dynamics is first designed, where both sampled position and velocity data are utilized. A necessary and sufficient condition based on the sampling period, the coupling gains, and the spectra of the Laplacian matrix, is established for reaching consensus of the system in this setting. It is found that second-order consensus in such a multi-agent system can be achieved by appropriately choosing the sampling period determined by a polynomial with order three. In particular, second-order consensus cannot be reached for a sufficiently large sampling period while it can be reached for a sufficiently small one under some conditions. Then, the coupling gains are carefully designed under the given network structure and the sampling period. Furthermore, the consensus regions are characterized for the spectra of the Laplacian matrix. On the other hand, second-order consensus in delayed undirected networks with sampled position and velocity data is then discussed. A necessary and sufficient condition is also given, by which appropriate sampling period can be chosen to achieve consensus in multi-agent systems. Finally, simulation examples are given to verify and illustrate the theoretical analysis. [ABSTRACT FROM PUBLISHER]

In the above paper [1], there are errors regarding the description of (4), and misquotes in Algorithm 1 and 2. In Algorithm 1, the first equation referenced should be (5) and not (40). In Algorithm 2, the first equation referenced should be (40) and not (5). The correction for (4) is as follows: \begin{equation*} \mathcal {L}^{(\sigma (t))}=\left [{\begin{array}{cc} \widetilde {\mathcal {L}}^{(\sigma (t))}& \mathrm {a}^{(\sigma (t))}\\ \mathrm {0}_{N}^{T}& 0 \end{array}}\right ] \tag{4}\end{equation*} where \widetilde \mathcal L^(\sigma (t))\in \mathbb R^N\times N , \mathrm a^(\sigma (t))=-[a1(N+1)^(\sigma (t)),a2(N+1)^(\sigma (t)),\cdots ,~aN(N+1)^(\sigma (t))]^{T}\in \mathbb {R}^{N} , and \mathcal A^(\sigma (t)) = [aij^(\sigma (t))](N+1) \times (N+1) is the adjacency matrix of \mathcal G^(\sigma (t)) . [ABSTRACT FROM AUTHOR]