虚假数据注入攻击下多智能体系统的均方二分一致性研究

研究在虚假数据注入(false data injection,FDI)攻击下带有过程噪声的多智能体系统的均方二分一致性问题.考虑智能体间的合作与竞争交互,在卡尔曼滤波框架下设计一种新颖的能够估计邻居智能体状态的算法,并从理论上证明算法的稳定性.与同类算法相比,该算法考虑了估计器测量范围内和测量范围外智能体的相关性.实验结果表明,相较于局部卡尔曼滤波算法,所提出估计算法具有更好的估计性能.在此基础上提出一种基于状态估计算法的安全保护机制,使智能体的状态更新能采用安全值,从而消除FDI攻击的影响,保障系统能够渐近实现均方二分一致性.最后通过数值实验对理论结果进行验证.     

基于观测器的多智能体系统安全一致性控制

针对混合攻击下多智能体系统基于观测器的事件触发一致性问题,设计观测器以估计智能体不可测的状态,引入事件触发机制以减少智能体的通信频次与控制器的更新频次。首先,考虑拒绝服务(DoS)攻击和重放攻击同时存在的情况,建立数学模型,并设计基于观测器的事件触发一致性控制协议。其次,针对不同的攻击情况,建立误差切换系统模型,并且采用分段Lyapunov函数方法得出误差系统均方指数稳定的充分条件。然后,通过求解一系列线性矩阵不等式,给出一致性控制器、观测器与事件触发参数的设计方法。最后,通过仿真实例证明了所提方法的可行性。     

DoS攻击下一类二阶多智能体系统的安全分组一致性研究

针对拒绝服务(denial-of-service, DoS)攻击下一类二阶多智能体系统的安全分组一致性协同控制问题,区别于同类工作,在非周期性多信道独立的攻击场景下,基于复杂系统中智能体间的合作与竞争交互,提出一种新的带有状态估计器的安全分组一致性控制协议.在该协议的作用下,首先,给出DoS攻击持续时间的约束条件,通过设计合适的李雅普诺夫函数,结合求解代数黎卡提方程得到不同攻击模式下信道的衰减率;然后,通过引入与各个信道对应的等效衰减率,克服所得衰减率与信道难以匹配的问题,并给出系统的稳定性判据;最后,通过数值实验验证理论分析所得结论的正确性和有效性.     

带扰动混杂多智能体系统领导–跟随一致性

本文研究了带扰动混杂多智能体系统领导–跟随一致性问题.给出了带扰动且含有非线性项的混杂多智能体系统模型.为了解决扰动和非线性项问题对系统带来的影响,本文基于等效趋近律设计了混杂多智能体系统的滑模控制协议,该控制协议包含连续时间智能体与离散时间智能体的运动状态信息.对混杂多智能体系统设计了Lyapunov函数,给出该系统实现领导–跟随一致性的充分条件,并证明了滑模控制协议下混杂多智能体系统可以实现领导–跟随一致性.最后,通过MATLAB仿真验证了所提方法的有效性.     

脉冲控制下基于合作机制的多智能体系统分组一致性研究

针对在脉冲控制下非线性多智能体系统的分组一致性协同控制问题,本文基于复杂系统中智能体间的合作机制,提出了一种新颖的具有领导-跟随网络的分组一致性控制协议.该协议控制智能体仅在脉冲时刻接收来自邻居节点的信息并更新自己的状态,减少智能体因持续接收邻居信息更新自己状态而造成的网络开销.针对不同组之间智能体的信息交互,该协议具有防止组间干扰的机制,降低了不同组之间的通信干扰,提高系统鲁棒性.此外,本文还介绍了一种适用于非线性系统的方案,增强协议的适应性.基于实现分组一致性条件,构建了多智能体系统的动力学模型,并进行了协议的详细设计和理论推导.最后,通过仿真验证了协议的正确性和有效性.     

重放攻击下多智能体系统H∞一致性PID控制

本文针对一类带有加性噪声和乘性噪声的离散多智能体系统,研究重放攻击下多智能体系统的H∞一致性比例–积分–微分(PID)控制问题.首先,根据智能体的测量输出设计状态观测器,对智能体的状态进行有效估计,观测器设计过程中考虑了系统测量输出从传感器传输到观测器过程中受到重放网络攻击的影响.然后,利用智能体与其邻居智能体的估计状态差设计PID控制器.利用李雅普诺夫稳定性理论和代数图论,证明在该控制策略下,多智能体系统在重放攻击存在的情况下达到预期的H∞性能指标.最后,利用线性矩阵不等式(LMI)方法求解观测器和控制器增益,利用数值仿真验证了所设计的观测器和PID控制器的有效性.     

基于噪声的非线性多智能体系统的均方一致性

本文主要研究拓扑结构为有向强连接的非线性多智能体系统的均方一致性问题.考虑到非线性系统中的个体在传递信息时受到噪声环境的干扰,提出一种新的延迟控制方案,提高了系统的控制性能.基于Lyapunov稳定性和Ito^积分方程理论,得到多智能体系统渐近趋于均方一致的充分条件.同时,得到相同的耦合强度下容许的最大延迟间隔,数值仿真结果进一步验证了理论分析的有效性.     

基于事件触发的二阶多智能体领导跟随一致性

研究二阶多智能体系统在固定有向拓扑下的领导跟随一致性问题.为了节省网络和计算资源,给出一种基于事件触发控制的一致性算法.针对每个跟随者智能体,设计基于状态误差形式的触发函数,只有当状态误差满足一定条件,即触发函数取值为零时智能体才触发事件,同时更新并传递自身的采样信息,在两个相邻事件触发时刻之间,控制输入只受领导者控制信号的影响.利用模型变换、矩阵理论和Lyapunov稳定性理论给出多智能体系统达到领导跟随一致性的充分条件.仿真结果验证了理论方案的可行性和有效性.     

有向图中网络Euler-Lagrange系统的自适应协调跟踪

基于一致性理论, 在有向图中研究网络 Euler-Lagrange 系统的协调跟踪控制. 所有跟随智能体的动力学模型均为 Euler-Lagrange 方程. 在仅有部分跟随智能体能获取领航智能体信息的情形下, 同时考虑系统模型的参数不确定性, 设计分布式自适应控制律实现所有跟随智能体对领航智能体的跟踪. 针对领航智能体的运动状态, 考虑以下两种情形: 1) 领航智能体为固定点; 2) 领航智能体为动态点. 对第一种情形, 设计的控制律使得所有跟随智能体渐近交会于固定点; 对第二种情形, 首先对每个跟随智能体设计分布式连续估计器, 然后提出了分布式自适应控制律. 当每个跟随智能体均能获取领航智能体的加速度信息时, 设计的控制律能实现对领航智能体的渐近跟踪, 当跟随智能体不能获取领航智能体的加速度信息时, 跟踪误差是有界的. 最后通过仿真分析验证设计的控制算法是合理有效的.     

带有输入时滞的领导跟随系统扰动抑制一致性

针对一类受到外部干扰且有输入时滞的多智能体系统,讨论了在固定有向拓扑下的领导跟随扰动抑制一致性问题。首先,对于存在外部干扰的多智能体系统,给出分布式状态观测器,使得每个智能体的系统状态和外部干扰被同时估计。其次,基于截取预测方法,利用邻居智能体相对输出信息获得的状态估计和自身干扰估计为每个智能体设计一致性协议。然后,用Lyapunov-Krasovskii理论对系统的观测性和稳定性进行分析,获得满足多智能体系统稳定的充分条件,并将控制器增益和观测器增益求解转化为求解线性矩阵不等式(LMIs)的形式。最后,通过一个仿真例子来验证所得结果的可行性和有效性。     

Leader-following consensus for single-integrator multi-agent systems with multiplicative noises in directed topologies

This paper proposes a leader-following consensus control for continuous-time single-integrator multi-agent systems with multiplicative measurement noises under directed fixed and switching topologies. The consensus controller is developed by combining the graph theory and stochastic tools. The control input for each agent relies on its own state and its neighbours’ states corrupted by noises, the noises are considered proportional to the relative distance between agents, both of the noisy case and the noise-free case are studied, and conditions to achieve mean square convergence under noisy measurement and asymptotic convergence in absence of noises are derived. Finally, in order to prove the validity of the consensus control, some simulations were carried out.     

DoS攻击下具备隐私保护的多智能体系统均值趋同控制

均值趋同是一种广泛应用于分布式计算和控制的算法, 旨在系统通过相邻节点间信息交互、更新, 最终促使系统中所有节点以它们初始值的均值达成一致. 研究拒绝服务(Denial-of-service, DoS)攻击下的分布式离散时间多智能体系统均值趋同问题. 首先, 给出一种基于状态分解思想的分布式网络节点状态信息处理机制, 可保证系统中所有节点输出值的隐私. 然后, 利用分解后的节点状态值及分析给出的网络通信拓扑条件, 提出一种适用于无向通信拓扑的多智能体系统均值趋同控制方法. 理论分析表明, 该方法能够有效抵御DoS攻击的影响, 且实现系统输出值均值趋同. 最后, 通过仿真实例验证了该方法的有效性.     

Mean square leader-following consensus of heterogeneous multi-agent systems with Markovian switching topologies and communication delays

This article considers the mean square leader-following output consensus problem of heterogeneous multi-agent systems under randomly switching topologies and time-varying communication delays. By modeling the switching topologies as a time-homogeneous Markov process and taking the communication delays into consideration, a distributed observer is proposed to estimate the state of the leader. A novel distributed output feedback controller is then designed. By constructing a novel switching Lyapunov functional, an easily-verifiable sufficient condition to achieve the mean square leader-following output consensus is given. Finally, two simulation examples are presented to show the effectiveness of the proposed control scheme.     

Leader-following consensus of multi-agent systems under directed communication topology via distributed adaptive nonlinear protocol

In this paper, we study the leader-following consensus problem of general linear multi-agent systems under directed communication topology. To avoid using any global information, an adaptive nonlinear protocol is proposed based only on the relative state information. It is proved that, for any directed communication graph that contains a spanning tree with the root node being the leader agent, the proposed control law solves the leader-following consensus problem. A numerical example is provided to illustrate the effectiveness of the theoretical results.     

Leader-following consensus of single-integrator multi-agent systems under noisy and delayed communication

This paper proposes a leader-following consensus control for continuous-time single-integrator multi-agent systems with multiplicative measurement noises and time-delays under directed fixed topologies. Each agent in the team receives imprecise information states corrupted by noises from its neighbours and from the leader; these noises are depending on the agents’ relative states information. Moreover, the information states received are also delayed by constant or time-varying delays. An analysis framework based on graph theory and stochastic tools is followed to derive conditions under which the tracking consensus of a constant reference is achieved in mean square. The effectiveness of the proposed algorithms is proved through some simulation examples.     

Leader-following consensus control of second-order nonlinear multi-agent systems with applications to slew rate control

This paper addresses the distributed leader-following consensus control of second-order strict-feedback nonlinear multi-agent systems. By employing mean value theorem, variable separation technique, and backstepping methodology, a fully distributed adaptive control law is designed using only local relative state information. The proposed control law solves the leader-following consensus problem for any directed communication graph that contains a spanning tree with the root node being the leader agent. The application to hovercraft slew rate control system is given to verify the effectiveness of the theoretical results.     

Dynamic-estimator-based adaptive secure containment control for constrained nonlinear multi-agent systems under denial-of-service attacks

This article concentrates upon the adaptive secure containment control problem for a class of uncertain nonlinear multi-agent systems with the output constraint requirements under denial-of-service (DoS) attacks. At first, to overcome the difficulty that the tracking performance of the nonlinear multi-agent systems under the DoS attacks is disturbed seriously, a novel adaptive secure containment control approach is presented by applying a DoS attacks detection mechanism and introducing the barrier Lyapunov functions, which enables the system to achieve the security control objective that the output of each agent eventually converges to the convex hull spanned by the dynamic leaders' outputs, while never violating the output constraints. Then, a state estimator is designed, which reconstructs the immeasurable states of the multi-agent systems and approximates the completely unknown nonlinearities arising from the agents. In addition, the dynamic surface control technique is used to solve the “explosion of complexity” problem. It is demonstrated that the proposed anti-attack controller ensures that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded. Finally, a simulation example is provided to illustrate the effectiveness of the theoretical results.     

Leader-following consensus of multi-agent systems under fixed and switching topologies

The leader-following consensus problem of higher order multi-agent systems is considered. In the system, the dynamics of each agent and the leader is a linear system. The control of each agent using local information is designed and detailed analysis of the leader-following consensus is presented for both fixed and switching interaction topologies, which describe the information exchange between the multi-agent systems. The design technique is based on algebraic graph theory, Riccati inequality and Lyapunov inequality. Simulations indicate the capabilities of the algorithms.     

自适应事件触发的马尔科夫跳变多智能体系统一致性

针对非线性马尔科夫跳变多智能体系统在有向固定拓扑下的领导跟随一致性问题,为减少智能体间不必要的通信传输,节约网络资源,保证系统性能,提出一种自适应事件触发控制策略.首先,将每一个智能体均视为马尔科夫跳变系统,且马尔科夫链的转移概率部分未知;通过简单的模型转换建立误差系统,将多智能体系统一致性问题转化为误差系统的稳定性问题;在此基础上,构造合适的Lyapunov-Krasovskii泛函并利用Jensen不等式和线性矩阵不等式等技术给出使多智能体系统达到领导跟随一致性的充分条件及控制器设计方法;通过求解线性矩阵不等式可以得到多智能体系统一致性控制器增益矩阵和事件触发参数矩阵;最后,通过数值仿真验证所提出方法的有效性.