一类离散时间异构多智能体系统有向图下的一致性分析

研究了离散时间一阶二阶混合的异构多智能体系统有向通信下的一致性问题。首先,对该系统内的个体分别提出了相应的一致性协议。针对该异构系统不满足离散时间系统研究中凸性要求的问题,本文引入了一个非奇异变换,采用非负矩阵理论和一致性理论,分别分析得出了系统在固定和动态拓扑下实现一致性的充分条件。当通信拓扑包含生成树,采样时间和控制参数在一定范围内取值系统将获得一致性,该范围取决于通信拓扑的度矩阵。最后,通过仿真对该结论进行了验证。     

Cluster-Delay Consensus for Second-Order Nonlinear Multi-agent Systems

This paper investigates the second-order nonlinear multi-agent systems subject to the cluster-delay consensus. The multi-agent systems consist of leader and agents, whose dynamics are second-order nonlinear. The objective is that the agents track the leader asymptotically with different time delays, i.e., the agents in different groups reach delay consensus, while the agents in the same group reach identical consensus. To guarantee the cluster-delay consensus for the second-order multi-agent systems, a new control protocol is proposed. Then some corresponding conditions for cluster-delay consensus are derived by using Lyapunov directed method and matrix theory. Finally, the effectiveness of the theoretical analysis results are verified by some numerical simulations.     

Consensus for Heterogeneous Multi-Agent Systems with Directed Network Topologies

In this paper, the consensus problem for heterogeneous multi-agent systems composed of first-order and second-order agents is investigated with directed network topologies. Based on a system transformation method, this consensus problem is turned into a consensus problem for homogeneous multi-agent systems. With certain assumption on the control parameters, firstly, necessary and sufficient condition for consensus is proposed with fixed topology. Secondly, sufficient condition is proposed for heterogeneous multi-agent systems to achieve consensus with switching topologies. Finally, simulation examples are presented to verify the effectiveness of the theoretical results.     

Leader-following consensus protocols for formation control of multi-agent network

Two protocols are presented,which can make agents reach consensus while achieving and preserving the desired formation in fixed topology with and without communication timedelay for multi-agent network.First,the protocol without considering the communication time-delay is presented,and by using Lyapunov stability theory,the sufficient condition of stability for this multi-agent system is presented.Further,considering the communication time-delay,the effectiveness of the protocol based on Lyapunov-Krasovskii function is demonstrated.The main contribution of the proposed protocols is that,as well as the velocity consensus is considered,the formation control is concerned for multi-agent systems described as the second-order equations.Finally,numerical examples are presented to illustrate the effectiveness of the proposed protocols.     

RELAXED CONDITIONS FOR CONSENSUS IN MULTI-AGENT COORDINATION

This paper proposes relaxed sufficient conditions for the consensus of multi-agent systems by the averaging protocols with time-varying system topology. Bidirectional information exchange between neighboring agents is considered and both the discrete-time and continuous-time consensus protocols are studied. It is shown that the consensus is reached if there exists an unbounded time sequence such that two agents who own the maximum and minimum states at each time instant in the sequence will be jointly connected at some future time. Further, this result is applied to the original nonlinear Vicsek model, and a sufficient condition for the heading consensus of the group with restricted initial conditions is obtained.     

Consensus of Heterogeneous Multi-Agent Systems with Intermittent Communication

This paper studies consensus of a class of heterogeneous multi-agent systems composed of first-order and second-order agents with intermittent communication. For leaderless multi-agent systems, we propose a distributed consensus algorithm based on the intermittent information of neighboring agents. Some sufficient conditions are obtained to guarantee the consensus of heterogeneous multi-agent systems in terms of bilinear matrix inequalities(BMIs). Meanwhile, the relationship between communication duration and each control period is sought out. Moreover, the designed algorithm is extended to leader-following multi-agent systems without velocity measurements. Finally, the effectiveness of the main results is illustrated by numerical simulations.     

Distributed Finite-Time Integral Sliding-Mode Control for Multi-Agent Systems with Multiple Disturbances Based on Nonlinear Disturbance Observers

This paper proposes a finite-time consensus control algorithm based on nonlinear integral sliding-mode control for second-order multi-agent systems(MASs) with mismatched and matched disturbances. Firstly, a nonlinear finite-time disturbance observer is established to estimate the states and mismatched disturbances of the agent. Secondly, a dynamic integral sliding-mode(ISM) surface is designed by employing the estimates of mismatched disturbances. Then, based on the designed ISM and disturbance observer, the discontinuous or continuous campsite control protocols are respectively developed to guarantee the consensus for MASs in finite time with active anti-disturbance control. Finally,numerical simulation results illustrate the effectiveness of the proposed consensus control algorithm.     

On control of strong consensus for networked agents with noisy observations

The discrete-time first-order multi-agent networks with communication noises are under consideration.Based on the noisy observations,the consensus control is given for networks with both fixed and time-varying topologies.The states of agents in the resulting closed-loop network are updated by a stochastic approximation(SA) algorithm,and the consensus analysis for networks turns to be the convergence analysis for SA.For networks with fixed topologies,the proposed consensus control leads to consensus of agents with probability one if the graph associated with the network is connected.In the case of time-varying topologies,the similar results are derived if the graph is jointly connected in a fixed time period.Compared with existing results,the networks considered here are in a more general setting under weaker assumptions and the strong consensus is established by a simpler proof.     

Robust Semi-Global Leaderless Consensus and Containment Control of Identical Linear Systems with Imperfect Actuators

This paper investigates both the robust semi-global leaderless consensus problem and the robust semi-global containment control problem for a group of identical linear systems with imperfect actuators. The imperfect actuators are characterized by nonlinearities such as saturation and dead zone and there input output relationships are not precisely known. The dynamics of follower agents are also affected by the input additive disturbances. Low-and-high gain feedback consensus protocols are constructed to solve these problems. More specifically, it is shown that robust semi-global leaderless consensus can be achieved over a connected undirected graph and robust semi-global containment control can be achieved when each follower agent has access to the information of at least one leader agent. Numerical simulation illustrates the theoretical results.     

Distributed tracking control of second-order multi-agent systems under measurement noises

This paper considers a leader-following tracking control problem for second-order multiagent systems（MASs） under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.     

具有不同输入时延的二阶多智能体系统一致性

研究了具有不同时变输入时延的二阶连续多智能体系统的一致性问题。首先,通过变量转换,将系统的收敛性问题转化为误差系统的稳定问题;然后,通过对系统进行变换,将二阶系统稳定性问题转换为等价系统的稳定性问题。通过构造李雅普诺夫函数,基于线性矩阵不等式(LMI)的方法,给出在无向固定拓扑条件下,系统达到一致的充分条件。最后,仿真实例证明了结果的有效性。     

Output consensus for heterogeneous nonlinear multi-agent systems based on T-S fuzzy model

In this paper, the output consensus problem of general heterogeneous nonlinear multi-agent systems subject to different disturbances is considered. A kind of Takagi-Sukeno fuzzy modeling method is used to describe the nonlinear agents’ dynamics. Based on the model, a distributed fuzzy observer and controller are designed based on parallel distributed compensation scheme and internal reference models such that the heterogeneous nonlinear multi-agent systems can achieve output consensus. Then a necessary and sufficient condition is presented for the output consensus problem. And it is shown that the consensus trajectory of the global fuzzy model is determined by the network topology and the initial states of the internal reference models. Finally, some simulations are given to illustrate and verify the effectiveness of the proposed scheme.     

Group consensus for multiple networked Euler-Lagrange systems with parametric uncertainties

In this paper,a group consensus problem is investigated for multiple networked agents with parametric uncertainties where all the agents are governed by the Euler-Lagrange system with uncertain parameters.In the group consensus problem,the agents asymptotically reach several different states rather than one consistent state.A novel group consensus protocol and a time-varying estimator of the uncertain parameters are proposed for each agent in order to solve the couple-group consensus problem.It is shown that the group consensus is reachable even when the system contains the uncertain parameters.Furthermore,the multi-group consensus is discussed as an extension of the couple-group consensus,and then the group consensus with switching topology is considered.Simulation results are finally provided to validate the effectiveness of the theoretical analysis.     

不完全信息下的群体决策仿真

为研究互联网个体交互,描述网络舆论演化与群体意见形成,建立了人员个性不完全信息博弈的策略选择模型,并对其进行了仿真和分析．根据网络交互的信息不对称性,提出了基于个体自信程度的不完全信息的支付矩阵,并使用海萨尼转换分析了博弈的贝叶斯纳什均衡;进一步地引入了个体记忆,通过交互进程更新了个体对邻居个性的认识．仿真结果表明,在不完全信息环境下,系统收敛时间更短,信息传播更快．研究内容有助于理解网络事件更易产生一致意见的演化规律,为网络舆论的引导策略提供参考和借鉴．     

Rebels Lead to the Doctrine of the Mean: A Heterogeneous DeGroot Model

The DeGroot model is one of the most classical models in the field of opinion dynamics. The standard DeGroot model assumes that agents are homogeneous and update their opinions in the direction of a weighted average of their neighbors’ opinions. One natural question is whether a second type of agents could significantly change the main properties of the model. The authors address this question by introducing rebels, who update their opinions toward the opposite of their neighbors’ weighted average. The authors find that the existence of rebels remarkably affects the opinion dynamics. Under certain mild conditions, the existence of a few rebels will lead the group opinion to the golden mean, regardless of the initial opinions of the agents and the structure of the learning network. This result is completely different from that of the standard DeGroot model, where the final consensus opinion is determined by both the initial opinions and the learning topology. The study then provides new insights into understanding how heterogeneous individuals in a group reach consensus and why the golden mean is so common in human society.     

A Class of Second-Order Consensus Protocol in Multi-Agent Systems with Multiple Input Delays

This paper is concerned with the consensus problems for second-order multi-agent systems with multiple input delays. Different from all standard consensus algorithms with uniform delays, the authors aim to find the largest input-delay margin which can guarantee the consensus for the case when delays are nonuniform. Based on frequency domain analysis and matrix theory, an upper bound for maximum tolerable input-delay is given in terms of the relationship with scaling strengths and largest eigenvalue of the Lapalician matrix. Simulation results are provided to illustrate the obtained results.     

Consensus problem of second-order multi-agent systems with time-varying communication delay and switching topology

Leader-following stationary consensus problem is investigated for the second-order multi-agent systems with timevarying communication delay and switching topology.Based on Lyapunov-Krasovskii functional and Lyapunov-Razumikhin functions respectively,consensus criterions in the form of linear matrix inequality (LMI) are obtained for the system with time-varying communication delays under static interconnection topology converging to the leader’s states.Moreover,the delay-dependent consensus criterion in the form of LMI is also obtained for the system with time-invariant communication delay and switching topologies by constructing Lyapunov-Krasovskii functional.Numerical simulations present the correctness of the results.     

Projective Group Consensus of Multi-Agent Systems with Arbitrary Parameter

In this paper, the projective group consensus issue for second order multi-agent systems(MASs) in directed graphs with a dynamic leader is investigated. The proposed projective group consensus with arbitrary parameter includes traditional consensus, reverse group consensus and cluster consensus as its special cases. Novel distributed control protocols are designed to obtain projective group consensus without analyzing signed directed graph as in most current literatures on bipartite consensus problem. On the basis of Lyapunov stability property, algebraic graph and some necessary matrix theory, sufficient conditions for delay and delay-free cases are derived. Finally, simulations of nonlinear chaotic MASs are adopted to testify the theoretical results.     

Consensus control for leader-following multi-agent systems with measurement noises

<正> This work is concerned with consensus control for a class of leader-following multi-agentsystems (MASs).The information that each agent received is corrupted by measurement noises.Toreduce the impact of noises on consensus,time-varying consensus gains are adopted,based on whichconsensus protocols are designed.By using the tools of stochastic analysis and algebraic graph theory,asufficient condition is obtained for the protocol to ensure strong mean square consensus under the fixedtopologies.This condition is shown to be necessary and sufficient in the noise-free case.Furthermore,by using a common Lyapunov function,the result is extended to the switching topology case.     

基于元胞自动机的网络群体事件舆论同步的涌现机制

以自发形成的网络群体事件的同步舆论为研究对象， 建立了基于元胞自动机的复杂系统集群行为的非线性涌现模型， 揭示了个体从众心理对网络舆论演化动力学的影响. 研究结果表明， 在个体从众性同质的情况下， 存在使网络舆论同步的阈值， 当个体从众性较大时， 网络群体事件舆论趋于同步； 当从众性较小时， 群体态度演化成具有明显社团结构的多个舆论方向. 个体从众性异质时， 网络舆论表现为一个主流舆论与多个小规模舆论方向共存的复杂特征. 网络群体事件发生初期， 参与规模的扩大会迅速促进舆论同步的涌现， 而在后期， 新节点的参与不会进一步提高舆论同步涌现的效率.