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In this paper, we discuss the cooperative output regulation problem for a class of heterogeneous linear multi-agent systems under undirected communication topological graph. First, an adaptive event-triggered protocol is introduced to achieve the consensus problem for leader-following system. Then, two fully distributed event-triggered adaptive control protocols are designed. That is, the state feedback and dynamic output feedback controllers, which does not need global information about network topology of system. Under the proposed two control protocols, the cooperative output regulation problem can be solved and no Zeno behavior happens for each agent. Finally, a numerical simulation is used to corroborate the validity of the conclusions under two control laws. Moreover, a comparative experiment is carried out to highlight the advantages of the control protocol designed in this paper. [ABSTRACT FROM AUTHOR]

This paper focuses on the study of the min–max consensus problem for multi-agent systems in random networks. A min–max consensus algorithm is proposed, which incorporates the weighted average of the agent's state, the maximum value of its neighbors' states, and the minimum value of its neighbors' states. The interaction network is composed of a directed random network where edges exist with probability and are independent of each other. Then, the convergence of the min–max consensus algorithm is investigated utilizing max-plus algebra, min-plus algebra, and stochastic analysis theory. Sufficient and necessary conditions are given to ensure that the multi-agent systems achieve min–max consensus almost surely and in mean-square, respectively. Finally, some numerical simulations are conducted to confirm the effectiveness of the proposed consensus algorithm. [ABSTRACT FROM AUTHOR]

This paper concentrates on the bipartite finite-time consensus (BFTC) problem of nonlinear multi-agent systems (MASs) under intermittent communication via event-triggered impulsive control. First, a finite-time consensus (FTC) protocol with an event-triggered mechanism is developed for the MASs with nonlinear dynamics to save limited resources. Then, an impulsive control scheme is introduced to the designed algorithm to further improve the control performance. Based on the structurally balanced graph theory, both antagonistic and cooperative interactions are discussed in this article. Regarding whether the MASs have encountered intermittent communication, sufficient conditions are provided for achieving consensus of the MASs by using the Lyapunov theory and inductive methods. Moreover, the Zeno behavior is excluded. Finally, numerical simulations are given to validate the effectiveness of the algorithm. The result shows that the designed event-triggered BFTC control protocol with an impulsive strategy has a faster convergence rate than that without an impulsive strategy. [ABSTRACT FROM AUTHOR]

Abstract This paper focuses on studying the distributed leader-following consensus problem of heterogeneous second-order time-varying nonlinear multi-agent systems (HSTN_MASs) under directed switching topology. Firstly, based on the relative position and relative velocity measurements among neighborhood agents, a class of distributed tracking protocols are proposed. Then the state transformations are provided to solve the time-varying nonlinearity and translate the leader-following problem into the stabilization control problem. By constructing the topology-dependent Lyapunov function and choosing appropriate time-varying regulation factor and coupling strength, it is shown that the exponential tracking of HSTN_MASs can be achieved. Moreover, this paper discusses the distributed leaderless consensus problem of HSTN_MASs. Finally, several simulation examples are given to illustrate the validity of theoretical results. [ABSTRACT FROM AUTHOR]

Highlights This paper studies the consensus problems for the two types of double-integrator fractional-order multi-agent system (DIFOMAS) with nonuniform time-delays: the DIFOMAS with symmetric time delays over undirected topology, and the DIFOMAS with asymmetric time delays over directed topology. The main contributions of this paper are as follows: • Consider the double-integrator fractional-order dynamics. • Consider the nonuniform time-delays, which contain up to n(n-1) different values when the DIFOMAS consists of n agents. • Consider the dynamics of each agent containing two state-variable with different fractional orders. • Obtain the two kinds of the upper bound of time-delays about Theorems 1 and 2 and the corollaries of Theorems 1 and 2. Abstract This paper addresses the distributed consensus control for a double-integrator fractional-order multi-agent system (DIFOMAS) with nonuniform time-delays. A general model of the DIFOMAS is introduced by such case: the dynamic model of each agent contains two state variables with different fractional orders. The consensus conditions on the two kinds of network topology and the nonuniform time-delays can be obtained by using the generic model: the DIFOMAS with symmetric time-delays over undirected topology, and the DIFOMAS with asymmetric time-delays over directed topology. With the help of matrix theory, Laplace transform and graph theory, two kinds of upper bounds of time-delays are derived to ensure the DIFOMAS with nonuniform time-delays can reach consensus. Finally, some numerical simulations with different parameters are offered to illustrate the feasibility and effectivity of the results derived. [ABSTRACT FROM AUTHOR]

This paper investigates the practical fixed-time event-triggered consensus problem of multi-agent nonholonomic systems with dynamic disturbances. The continuous communications can be avoided in the update of controller. By converting the nonholonomic chained systems into two subsystems, a switching control algorithm was proposed to deal with the coupling problem in systems. Compared with the event-triggered fixed-time consensus problem of first-order or second-order linear systems, the research of nonholonomic chained systems is more challenging due to the inherent nonlinearity of these systems. Moreover, the convergence time of fixed-time consensus problem is independent of initial states, which is more practical than finite-time consensus problem. Furthermore, it is proved that there is no Zeno behavior under the fixed-time event-triggered consensus control strategies. The effectiveness of the proposed control algorithms is verified by numerical simulations. [ABSTRACT FROM AUTHOR]

This paper considers the leader-following bipartite consensus for a class of nonlinear multi-agent systems (MASs) subject to exogenous disturbances under directed fixed and switching topologies, respectively. Firstly, two new output feedback control protocols involving signs of link weights are introduced based on relative output measurements of neighboring agents. In order to estimate the disturbances produced by an exogenous system, a disturbance observer-based approach is developed. Then, sufficient conditions for leader-following bipartite consensus with directed fixed topologies are derived. Furthermore, by assuming that each switching topology contains a directed spanning tree, it is proved that the leader-following bipartite consensus can be realized with the designed output feedback control protocol if the dwell time is larger than a non-negative threshold. Finally, numerical simulations inspired by a real-world DC motors are provided to illustrate the effectiveness of the proposed controllers. [ABSTRACT FROM AUTHOR]

A continuous-time distributed algorithm based on multi-agent systems is proposed to solve the convex nonsmooth optimization with globally coupled constraints in this paper. Firstly, the relationship of equivalence between the equilibrium and the optimal solution of the system is proved by using the properties of projection operator and saddle point. In addition, the stability of the algorithm is analyzed by means of Lie derivative and set-valued LaSalle's invariance principle. In particular, the trajectory of the proposed algorithm from any initial point can converge to the global optimal solution. Finally, the effectiveness of the designed algorithm is verified by numerical simulations. [ABSTRACT FROM AUTHOR]

This paper studies the differential privacy-preserving problem for multi-agent systems (MASs) in the presence of antagonistic information over signed digraph. As for the structurally balanced case, an ε -differential privacy algorithm is proposed, upon which some sufficient conditions guaranteeing almost sure bipartite consensus are given. Based on the above scheme, the tradeoff between the system performance and the privacy guarantee is elaborated, and the optimal noise is also devised. Moreover, the proposed privacy preserving scheme is further applied to the scenario of structurally unbalanced graph, where a criterion with respect to almost sure stability of the considered system is derived, as well as the privacy preserving condition. This extends the balanced interaction scenario, and consequently the cooperative multi-agent systems. Finally, numerical simulations are presented to demonstrate the effectiveness of our results. [ABSTRACT FROM AUTHOR]

Distinguished from the stationary group consensus problem, in this paper, the dynamic group consensus for a class of heterogeneous multi-agent systems under the influence of input time delays is investigated. A novel dynamic group consensus protocol is designed, where the coexisted cooperation and competition interaction relationships among the agents are considered. Two cases including identical and diverse input time delays are discussed, respectively. Based on matrix theory, system stability theory and pinning control strategy, some sufficient conditions for the heterogeneous systems are established to achieve dynamic group consensus asymptotically. The obtained results reveal that the achievement of systems' dynamic group consensus is related to systems control parameters, the in-degree and input time delays of the agents. Finally, the effectiveness of our theoretical results is verified by some numerical simulations. [ABSTRACT FROM AUTHOR]

This paper investigates the flocking control issue of multi-agent systems, where each agent utilizes the broadcasting communication manner and takes the Cucker–Smale style dynamic model. In the setting of broadcasting scenario, each agent broadcasts the state information only at certain moments determined by its own clock, and recalculates the control input only when its clock ticks or it receives information from the neighbors. In the Cucker–Smale model, a nonlinear weight function about the communication distance is set to portray the mutual influence degree between agents. With the help of the properties of sub-stochastic matrix, a comprehensive analysis of the asymptotic convergence of the model is performed and the algebraic conditions for achieving flocking control are established. In addition, the obtained theoretical results are further extended to the bipartite flocking control issue for multi-agent systems with both cooperative and competitive interactions. At last, numerical simulations are provided to verify the theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, the distributed cooperative control problem of heterogeneous nonlinear multi-agent systems (HNMASs) which are of pure-feedback forms coupled with nonaffine dynamics is considered with momentous emphasis on finite-time convergence. Multiple kinds of input constraints are also considered and can be completely unknown. To achieve the dynamic tracking for the heterogeneous followers with unknown input constrains, there are two consensus theorems are proposed, one of which can be utilized to achieve finite-time convergence. Meanwhile, it is the blend of fraction power feedback method and neural network (NN) technique that let the controlled systems have the finite-time characteristic. In the proposed tracking control protocols, only the local position information from neighbors or leader is required. In the end, the effectiveness of two proposed consensus algorithms is confirmed and compared by numerical simulation. [ABSTRACT FROM AUTHOR]

In this paper an agent-based social contagion model with an underlying dynamic network is proposed and analyzed. In contrast to the existing social contagion models, the strength of links between agents changes gradually rather than abruptly based on a threshold mechanism. An essential feature of the model – the ability to form clusters – is extensively investigated in the paper analytically and by simulation. Specifically, the distribution of clusters in random and scale-free networks is investigated, the dynamics of links within and between clusters are determined, the minimal distance between two clusters is identified. Moreover, model abstraction methods are proposed by using which aggregated opinion states of clusters of agents can be approximated with a high accuracy. These techniques also improve the computational efficiency of social contagion models (up to 6 times). [ABSTRACT FROM AUTHOR]

This paper studies the consensus problem of multi-agent systems (MASs) with false data injection (FDI) attacks and noises. Based on the graphical method and Kalman filter framework, distributed state estimators are designed for the agents to estimate the states of neighbors. A threshold comparison approach is proposed to obtain the secure states. Combining the state estimation approach with the threshold scheme, security mechanism is put forward to ensure the mean square consensus of MASs subject to FDI attacks. Finally, numerical simulations are provided to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

This paper investigates consensus of linear multi-agent systems (MASs) with exogenous disturbances and intermittent communication. Based on a disturbance-observer method, both distributed state feedback and output feedback intermittent consensus protocols are proposed by using estimated disturbance and local relative information. And the consensus conditions are obtained by using Lyapunov stability theory. Finally, two numerical simulation examples are given to illustrate the proposed theoretical results. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of bipartite output consensus of heterogeneous linear multi-agent systems with antagonistic interactions. The signed graph is directed and structurally balanced. With the assumption that only the leader can access the output of exosystem, two fully distributed adaptive protocols without using the state information of exosystem are designed based on the states and the observers of states, respectively. Numerical simulation demonstrates the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper focuses on the control of spherical formation for multi-agent systems with double-integrator dynamics in three-dimensional space. To achieve the desired formation pattern on a spherical surface, N agents must be distributed evenly around a target. Based on the information gathered about the target and its immediate neighbors, all agents can either remain stationary or rotate around the target at the same velocity on a spherical surface while the target moves in three-dimensional space. A decoupled control method with limit cycle oscillator characteristics is explored to achieve the desired formation geometric pattern. Accordingly, three subproblems are proposed to achieve the spherical formation more effectively. The first subproblem, target-spherical-surface , requires the agents to converge on a specified spherical surface with the target as its center. The second subproblem, target-circling , requires the agents to follow three prescribed orthometric circular orbits on the spherical surface to avoid collisions while moving. The final subproblem is distributed-adjustment , which involves agents to maintaining a prescribed angular distance from their immediate neighbors while remaining relatively stationary or rotating around the target. By addressing the first two sub-problems simultaneously, the agents can be guided to the desired position. The properties of the limit-cycle-based spherical formation controller are analyzed theoretically, and its effectiveness is demonstrated through numerical simulations. [ABSTRACT FROM AUTHOR]

This paper researches the adaptive bipartite output containment problem, for a signed graph of heterogeneous multi-agent systems (HMASs). The dynamics of leaders are subject to unknown but bounded inputs, which cannot be measured by followers. Therefore, an containment control protocol based on distributed observer is proposed. An adaptive state and an output feedback algorithm are designed to ensure that cooperative and antagonistic agents enter different convex hull. Then, based on the output regulation approach, Lyapunov stability analysis and some other methods, the bipartite output containment control is realized. Finally, we validate the analytical results by numerical simulations. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the adaptive consensus problem of multi-agent nonlinear systems with odd impulsive sequence. To reduce the required information transmitted among the nodes, the distributed impulsive control protocol is designed. Considering the unknown system parameters in real system, the adaptive control technique is also used and some novel sufficient consensus conditions are derived to achieve the consensus of multi-agent nonlinear systems. The proposed odd impulsive control can obtain larger control region than the common impulsive consensus method with fixed impulsive instants, which is more flexible and reliable in practical application. Finally, two simulations are given to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with optimizing the distribution of services performed by agents in a mobile agent network (MAN) using a genetic algorithm. The MAN is a model which consists of agents and various network elements and nodes. Each agent is capable of performing remote software management services. In order to verify the efficiency of various service distributions on different network topologies, we developed a mobile agent network simulator. This simulator allows the user to define the services which need to be performed by agents and describe the physical network used in the process. In this paper, an approach using a genetic algorithm is proposed. This algorithm is used to generate a suboptimal distribution of services among agents which optimizes the total execution time of services on a variety of network topologies with different network parameters. [Copyright &y& Elsevier]

In this paper, the robust consensus problem of fractional-order multi-agent systems with input saturation and external disturbances is studied under a directed fixed topology. It’s the first time to consider the fractional-order agent subject to input saturation. When there exist input saturation and external disturbances simultaneously, by means of the Mittag–Leffler stability theorem and low gain feedback technique, a control protocol is presented to guarantee the robust consensus can be achieved. Moreover, as a special case, the leader-following consensus can be achieved when there only exists input saturation. Finally, the results are verified by several simulation examples. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the second-order consensus problem of discrete-time multi-agent systems with fixed and switching topology. Impulsive protocols are introduced for such multi-agent systems with nonlinear dynamics. The consensus problem of multi-agent systems is analyzed by algebraic graph theory and matrix theory, where a connection of impulsive control methods and network topologies is established. Our main results indicate that the second-order consensus of multi-agent systems can be achieved if the graphs of the topology are balanced and strongly connected under suitable conditions. Numerical simulations are presented to support the theoretical results. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of distributed leader-following consensus for a multi-agent system with an affine nonlinear term. The communication topology we adopt is an undirected connected graph and the leader sends its information to one or more followers. To make each follower asymptotically synchronize with the leader, a nonlinear distributed control protocol is proposed. Using a Lyapunov function and a matrix theory, we establish sufficient conditions which ensure the consensus of these nonlinear multi-agent systems. Finally, a numerical simulation is provided to verify the effectiveness and usefulness of the developed method. [ABSTRACT FROM AUTHOR]

In this paper, a distributed event-triggered algorithm was proposed to solve a convex quadratic optimization problem of multi-agent systems under undirected and connected topologies. The event-triggered condition of each agent just requires its own state value and the state values of its neighbors at the triggering time, and hence the continuous communication and calculation are not required. Moreover, the minimum event-triggered interval is bounded by the sampling time and the Zeno behavior is therefore naturally avoided. The result is also extended to the networks with undirected and switching topologies. Numerical simulations show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper studies the circle formation control for second-order integrator multi-agent systems with event-triggered control strategy. Centralized and decentralized event-triggered control laws are proposed and two corresponding event-trigger conditions are derived respectively using Lyapunov method. With the designed strategies and event-trigger conditions, the second-order system can achieve circle formation control. Finally, numerical simulations are given to illustrate the effectiveness of the proposed event-triggered control strategy. [ABSTRACT FROM AUTHOR]

This paper presents a decentralized event triggered cooperative control design for uncertain multi-agent systems under limited communication resources. A local estimator is employed by each agent to generate self-state estimates. The estimated states are directly used in the consensus control design, and the estimator parameters are used in the event condition design. Once an event is triggered, the local estimator is repeatedly reset to its corresponding real state values, such that it can stabilize the uncertain dynamical systems without knowing the exact system model parameters. A theorem for this triggering condition is developed to provide stable thresholds that are robust to model uncertainties and guarantee the asymptotical stability by exploiting the M-matrix, algebraic graph theory and the Lyapunov method. It is rigorously proved that the overall system will achieve the consensus and has no zeno behavior under the introduced triggering condition. Simulation results are provided to show the effectiveness of the proposed decentralized event-triggered cooperative control strategy. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to study average consensus problems in multi-agent networks with switching topologies under digital communication channels. A novel communication framework that can smoothly combine the quantization scheme and event-triggered strategy is developed, which apparently improves the communication efficiency of networks. In pursuit of saving the network resource and reducing the computational load of microprocessors embedded in all agents, a specifically designed distributed event-triggered strategy is proposed for well treatment with consensus problems in digital networks with switching topologies. Furthermore, we also prove that the average consensus of networks is asymptotically achieved, and the states evolution of all agents is well. Finally, some numerical simulations are given to illustrate the correctness of the theoretical results and the feasibility of presented protocols. [ABSTRACT FROM AUTHOR]

This paper establishes a novel finite-time containment control framework for multi-agent systems such that the containment control problem can be solved at any preset time with static or dynamic leaders. In order to reach this goal, nonlinear feedback control protocols are introduced. We prove that the proposed protocols can solve containment problems at the preset time if the communication graph has a spanning forest. Numerical simulations are presented to illustrate the effectiveness of the obtained theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, formation-containment control problems for multi-agent systems with second-order dynamics and time-varying delays are studied. The states of leaders are designed to achieve the time-varying formation and the states of followers are required to converge to the convex hull spanned by those of leaders simultaneously, which differs from conventional formation control or containment control problems. Using the neighboring positions and velocities, formation-containment protocols with time-varying delays are constructed. By exploiting the space decomposition approach, formation-containment problems are transformed into the asymptotically stable problems. Sufficient conditions for second-order multi-agent systems with time-varying delays to realize formation-containment are presented. A method to obtain the unknown gain matrices in the protocols is proposed. Numerical simulations are shown to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper investigates the guaranteed cost consensus problem for multi-agent systems with actuator faults/uncertainties. For the leaderless case with actuator faults, a global performance index is constructed by all states and control inputs of all agents, where consensus regulation performances and control energy costs are considered simultaneously. Then, based on the relative state information of neighboring agents, a distributed cooperative guaranteed cost controller is designed, which not only makes the consensus problem solvable but also provides an upper bound of the given global performance index even in the presence of actuator faults. Extensions to the leader-following case with actuator faults and uncertainties are further studied. Finally, two simulation examples are provided to show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

In line of the research on leader-following consensus, this paper studies the consensus problem for the first-order multi-agent system with a smart leader. Different from previous works where the leader is independent of all the other agents, a kind of leader, called smart leader, is proposed, which can gain and utilize its neighboring followers' position information. Whether such information will be used in adjusting the control algorithm for the smart leader is decided by an event-trigger function. The theory and simulation results show that the proposed model can gain advantage in robustness and fault-tolerance ability with the traditional one. Moreover, a sufficient condition is provided, which can ensure that the position-tracking error and velocity-tracking error are bounded when some actuator faults occur on some of the followers in the framework of the fixed topology. In addition, similar results are also given under switching topology. Finally, some simulation examples are presented for illustration. [ABSTRACT FROM AUTHOR]

Consensus can be achieved under various topologies for multi-agent systems. Then, which one is the optimal? In this paper, we consider the problem of optimal topology for consensus of heterogeneous multi-agent systems. We assume that the system consists of a leader and several followers with heterogeneous dynamics. Firstly, we define a quadratic cost function composed of consensus error and control effort for the heterogeneous multi-agent system. Secondly, by using linear-quadratic regulator theory and matrix theory, we prove that the optimal position topology and the optimal velocity topology are star graphs. Finally, simulations are carried out to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper studies the coordination of nonlinear multi-agent systems with multiple leaders and stochastic disturbance. Two impulsive control algorithms are proposed to make all agents to track the convex set determined by the multiple leaders under both fixed and switching topologies. Based on Lyapunov function and comparison principle of impulsive systems, some results on the convergence of the controlled systems are obtained. Finally, some numerical simulations demonstrate the validity of the proposed control algorithms. [ABSTRACT FROM AUTHOR]

Multiple coordination corresponds to a diversified synchronous regime where different subgroups in one multi-agent system may emerge several distinct collective behaviors respectively. This paper is devoted to propose and analyze hybrid subgroup coordination of multi-agent systems under generic directed topologies. Due to unanticipated practical situations, agents in one subgroup are supposed to achieve a synchronous scenario asymptotically, such as average of agents’ initial states or its bounded region, while there is no agreement between any two distinct subgroups. Certain assumptions are imposed on the underlying topology for agents to evolve into several subgroups. Explicit distributed control algorithms are designed by adopting nonidentical extra-subgroup and intra-subgroup information exchange, and detailed convergence analysis is presented based on techniques of graph and matrix. Relevant simulation work is further carried out to illuminate the developed theoretical results. [ABSTRACT FROM AUTHOR]

This paper investigates distributed containment control problems for second-order nonlinear multi-agent systems with dynamic leaders. In the presence of bounded unknown nonlinearity, a distributed control algorithm based on High-frequency Feedback Robust Control is proposed. Under this algorithm, a sufficient condition is proposed to ensure that all the followers will converge to the dynamic convex hull formed by dynamic leaders and the containment error can be ultimately bounded for the directed graph where at least one leader has a directed path to each follower and the communication among the followers are undirected. Numerical simulations are also presented to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper addresses the robust consensus problem of fractional-order linear multi-agent systems with positive real uncertainty where the fractional-order α satisfies 0 < α < 2 . For multi-agent systems with fixed undirected topology, a distributed protocol is proposed based on the information of second-order neighbors. Then, new LMI-based sufficient conditions for robust consensus of fractional-order multi-agent systems are obtained and the feedback matrix is also determined accordingly. Finally, numerical simulation examples are presented to demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper considers the cooperative robust output regulation for second-order discrete-time multi-agent systems. Each agent could access the information with its neighbors under the directed network topology. A distributed dynamic state feedback control law is designed. A stability region is given for the discrete-time multi-agent systems, and internal model method is used for the robust output regulation problem. At last, numerical simulation is utilized to show the effectiveness of the obtained results. [ABSTRACT FROM AUTHOR]

For the multi-agent community, one of the key challenges is the agents operating in open environments, in which stochastic noises affect the dynamics of agents. This paper deals with the leader-following consensus problem for a class of linear multi-agent systems model with randomly occurring nonlinearities and uncertainties, and stochastic disturbances. The communication topology is assumed to be undirected and fixed. The stochastic Brownian motions are used to describe the source of extrinsic disturbances. The randomly occurring nonlinearities are introduced to describe the nonlinear intrinsic dynamics occurring in a probabilistic way. The randomly occurring uncertainties are adopted to reflect more realistic dynamical behaviors of the agent systems that are caused by noisy environment. Sufficient conditions are derived to make all follower agents asymptotically reach the state of leader in the mean square sense. Simulation results illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, a group consensus problem is investigated for the heterogeneous agents that are governed by the Euler-Lagrange system and the double-integrator system, respectively, and the parameters of the Euler-Lagrange system are uncertain. To achieve group consensus, a novel group consensus protocol and a time-varying estimator of the uncertain parameters are proposed. By combining algebraic graph theory with the Barbalat lemma, several effective sufficient conditions are obtained. It is found that the time-delay group consensus can be achieved provided that the inner coupling matrices are equal in the different sub-networks. Besides, the switching topologies between homogeneous agents are also considered, with the help of the Barbalat-like lemma, and some relevant results are also obtained. Finally, these theoretical results are demonstrated by the numerical simulations. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we focus on investigating group consensus of dynamical multi-agent networks via pinning scheme. The topology of the network is a general digraph, which needs neither being symmetric nor containing a spanning directed tree, and some criteria are proposed to guarantee the realization of group consensus instead of relying on other conservative assumptions presented by majority of the relevant research works, such as in-degree balance. In addition, it is interesting to find that the nodes with zero in-degree should be pinned first based on the property of M-matrix. Furthermore, an adaptive pinning control approach is developed to obtain the appropriate control gains. Finally, the effectiveness and correctness of our theoretical findings are verified by some numerical simulations. [Copyright &y& Elsevier]

Abstract: In this paper, we first investigate the fundamentals of the immune system and the principles of the antibodies and how antibodies work cooperatively to achieve swarm coordination and hence a successful immune response. Based on the study, we propose a multi-agent cooperative operation strategy for the immune system based on the immune network theory. In order to achieve successful swarm coordination, we design each agent to select its favorable strategy according to distributed sensing through local communication. Experiments show that this Immunology-inspired Cooperative Operation strategy performs well even under dynamically changing environment. Its effectiveness is also verified by numerical simulation on multiple unmanned aerial vehicle (UAV) coordination. [Copyright &y& Elsevier]

Abstract: This paper deals with the output regulation problem of the nonlinear multi-agent systems based on dynamic neural networks. Assume that the models of following agents in the considered systems are unknown, and the state of the leader agent is not completely measurable for each follower. By employing Lyapunov approach, a dynamic neural network is established to approximate the systems of the following agents. Based on the dynamic neural network, a state feedback control law is designed guaranteeing the following agents can asymptotically track the reference generated by an exosystem. The exosystem is regarded as the active leaders in the multi-agent systems. A numerical simulation example is provided to demonstrate the effectiveness of the obtained results. [Copyright &y& Elsevier]

Abstract: This paper investigates output regulation problem of state-coupled linear certain and uncertain multi-agent systems with globally reachable topologies. Distributed dynamic state feedback control law is introduced to realize the regulator problem and a general global method for error regulation is established. The Jordan canonical form is used to stabilize the closed-loop control system. Sylvester equation and internal model theory are adopted to achieve the objectives of output regulation for every initial condition in the state space. Finally, numerical simulations are utilized to show the effectiveness of the obtained results. [Copyright &y& Elsevier]

Abstract: This paper investigates a flocking problem of multiple agents with heterogeneous nonlinear dynamics. In order to avoid fragmentation, we construct a potential function and a connectivity-preserving flocking algorithm to enable the multiple agents to move with the same velocity while preserving the connectivity of underlying networks with a mild assumption that the initial network is connected and the coupling strength of the initial network of the nonlinear velocity consensus term is larger than a threshold value. Furthermore the proposed flocking algorithm is extended to solve the problem of multi-agent systems with a nonlinear dynamical virtual leader. The result is that all agents' velocities asymptotically approach to the velocity of the virtual leader, and the distance between any two agents is asymptotically stabilized to avoid collisions among agents. Finally, some numerical simulations are presented to illustrate the effectiveness of the theoretical results. [Copyright &y& Elsevier]