Sampling Consensus of 2nd-Order Multi-Agent Systems Based on Time-Varying Topology北大核心CSCD

基于速度一致位移差保持不变的一致性概念,研究了二阶多智能体系统在时变拓扑下的采样一致性问题。首先,引入虚拟领导者,将具有时变拓扑结构的多智能体系统的采样一致性问题转换为误差系统的采样控制稳定性问题。其次,通过预估采样误差,研究采样误差对系统达到一致性的影响。最后,应用Lyapunov稳定性理论,分析所构造的误差系统的稳定性,并给出该误差系统最终稳定的充分条件。数值仿真结果验证了理论分析的有效性和正确性。     

马尔科夫切换拓扑下带有非一致时变时滞的多智能体系统的H_∞领导跟随一致性问题

研究马尔科夫切换拓扑下带有非一致时变时滞的多智能体系统的H_∞领导跟随一致性问题.通过一个模型变换,把原系统的领导跟随一致性问题转化为新的误差系统的均方稳定性问题.根据马尔科夫时滞系统的稳定性理论,以线性矩阵不等式的形式给出了多智能体系统实现领导跟随一致且具有给定的H_∞性能指标的充分条件.最后,仿真实例验证了理论结果的有效性.     

一阶多智能体系统的一致性分析

研究一阶连续多智能体系统的一致性问题,其中每个智能体只能在一系列离散时刻上获得其相对邻居的状态信息,并且每个智能体的保持器的周期和采样器的周期是不同的.通过分析多智能体系统的稳定性,获得了一致性成立的充要条件,该条件揭示了交流拓扑、控制器增益、采样器的周期和保持器的周期的关系.最后,提供一个仿真例子以说明理论结果的有效性.     

具有领导者的非线性分数阶多智能体系统的一致性分析

研究了利用非线性分数阶模型描述的具有领导者的多智能体系统的一致性问题.基于智能体之间的通讯拓扑图,设计了系统的控制协议和相应的控制增益矩阵.利用广义Gronwall不等式和分数阶微分方程的稳定性理论,得到了多智能体系统达到一致的充分条件.最后,数值仿真结果显示了理论结果的有效性.     

四阶偏微分多智能体系统的迭代学习控制

该文研究多智能体系统基于一致性收敛的迭代学习控制问题,该系统中所有的智能体是由四阶梁方程构建而成.基于网络拓扑结构,并利用相邻智能体的信息,构建得到基于一致性的迭代学习控制协议.当该迭代学习律作用于系统时,一致性误差在给定的有限时间段上有界;进一步,在无初始偏差情形下,当迭代次数趋于无穷时,该一致性误差于L~2空间中能够收敛于零.仿真算例验证了算法的有效性.     

随机切换拓扑下具有区间时变时滞的二阶离散多智能体系统的均方包含控制

研究随机切换拓扑下具有区间时变时滞的二阶离散多智能体系统的均方包含控制问题.通过一个变量变换,把原系统的均方包含控制问题转化为新系统的均方稳定性问题.根据随机稳定性理论和线性矩阵不等式的方法,给出了多智能体系统解决均方包含控制的充分条件.最后,仿真实例验证了理论结果的有效性.     

带有时滞的离散多智能体系统的H_∞一致性问题

考虑带有时滞的离散多智能体系统的H_∞一致性问题,采用增广系统法将原系统转换成为一个不带时滞的降阶系统.通过利用李雅普诺夫稳定性理论研究降阶系统的稳定性,得到多智能体系统达到H_∞一致的线性矩阵不等式形式的条件.最后,仿真结果验证理论结果的有效性.     

DoS攻击下多智能体系统的事件触发编队控制

文章研究了拒绝服务(DoS)攻击情况下多智能体系统基于事件触发的编队控制问题.首先,基于系统状态构造了一种滑模编队控制算法,有效地克服外部干扰并实现时变编队.为了避免控制资源浪费,将事件触发策略应用于多智能体系统的编队控制中,并对奇诺(Zeno)现象的避免进行了详细的分析.假设DoS攻击是周期性发生的,针对具有DoS攻击的多智能体系统,提出了一种改进的触发机制,使其仍然能完成编队控制任务,并通过Lyapunov函数法和归纳法证明了控制系统的稳定性.最后,仿真结果验证了该方案的有效性.     

高阶离散时间多智能体系统的量化一致性

研究高阶线性多智能体系统在有向量化链路信息拓扑下的一致性问题,首先提出了包含智能体自身与其邻居量化信息的线性一致性协议,其次利用提出的线性变换,将一致性问题转化为稳定性问题,基于稳定性理论,得到基于矩阵Schur稳定性的充要条件,并得到依赖于信息拓扑、系统动态和整个系统初始状态的一致性函数,最后,通过求解代数Riccati不等式,提出增益矩阵的设计过程.     

基于二阶邻居信息的高阶多智能体系统的一致性

研究了基于一阶和二阶邻居信息的二阶和高阶丢包多智能体系统一致性问题.对于离散框架下的多智能体系统,假设智能体之间通信拓扑图是无向的,数据包的丢失服从伯努利分布.考虑到丢包问题,文章利用一阶和二阶邻居信息针对二阶和高阶系统给出了控制协议。基于李雅普诺夫函数方法,建立了闭环系统的均方稳定性条件.算例的仿真验证了所提控制策略的有效性.仿真表明由于利用了二阶邻居信息,数据包丢失的多智能体系统具有更快的收敛速度.     

Stability preserving model reduction for linearly coupled linear time-invariant systems

We develop a stability preserving model reduction method for linearly coupled linear time-invariant (LTI) systems. The method extends the work of Monshizadeh et al. for multi-agent systems with identical LTI agents. They propose using Bounded Real Balanced Truncation to preserve a sufficient condition for stability of the coupled system. Here, we extend this idea to arbitrary linearly coupled LTI systems using the sufficient condition for stability introduced by Reis and Stykel. The model reduction error bounds for this method also follow from results of Reis and Stykel, which allows the adaptive choice of reduced orders. We demonstrate the method on Reis's and Stykel's coupled string-beam example. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

基于牵制控制的多智能体系统的有限时间与固定时间一致性

主要研究了在有限时间与固定时间内,牵制多智能体系统到异质目标节点的问题.通过设计非连续的控制协议和两种有效的牵制方案,使得一群有向协作个体在有限时间内或者固定时间内与目标节点达到一致.利用微分包含、集值映射及Lyapunov稳定性理论,给出了多智能系统达到有限时间一致性和固定时间一致性的充分条件.最后,通过数值仿真验证了所得条件的有效性.     

Approximate homomorphisms on lattices

We prove two results concerning an Ulam-type stability problem for homomorphisms between lattices. One of them involves estimates by quite general error functions; the other deals with approximate (join) homomorphisms in terms of certain systems of lattice neighborhoods. As a corollary, we obtain a stability result for approximately monotone functions.     

Edge agreement of second-order multi-agent system with dynamic quantization via the directed edge Laplacian

This work explores the edge agreement problem of second-order multi-agent systems with dynamic quantization under directed communication. To begin with, by virtue of the directed edge Laplacian, we propose a model reduction representation of the closed-loop multi-agent system depending on the spanning tree subgraph. Considering the limitations of the finite bandwidth channels, the quantization effects of second-order multi-agent systems under directed graph are considered. The static quantizers generally contain a fixed quantization interval and infinite quantization level, which are, to some extent, inefficient and impractical. To further reduce the bit depth (number of bits available) and to obtain better precision, the dynamic quantized communication strategy referring to zooming in-zooming out scheme is required. Based on the reduced model associated with the essential edge Laplacian, the asymptotic stability of second-order multi-agent systems under dynamic quantized effects with only finite quantization level can be guaranteed. Finally, the simulation of altitude alignment of micro air vehicles is provided to verify the theoretical results.     

A new class of fixed-time bipartite flocking protocols for multi-agent systems

This work is concerned with the fixed-time stability theorem and the fixed-time bipartite flocking with collision avoidance for multi-agent systems. Under the framework of Filippov solution, a new theorem of fixed-time stability is established and a high-precision estimation of settling time is given. As an important application, the fixed-time bipartite flocking protocol of nonlinear multi-agent systems is proposed. Employing this fixed-time stability theorem and the structurally balanced signed graph theorem, the bipartite flocking without collision is achieved within a fixed-time. Moreover, the convergent time of the bipartite flocking is merely depending on the parameters of the protocol and the network connectivity. In addition, the upper bound of the size for each disjoint cluster can be estimated by the parameters of the protocol, the network connectivity and the initial states of the system. These results are novel, which are illustrated by both theoretical analysis and numerical simulations.     

离散时间大种群随机多智能体系统的线性二次分散动态博弈

研究具有耦合二次型随机性能指标的离散时间大种群随机多智能体系统的分散博弈问题.系统所受的噪声干扰为条件二阶矩有界的鞅差序列,比以往研究所考虑的高斯白噪声情形更具有广泛性.采用状态聚集方法构造了对种群状态平均的估计,基于Nash必然等价原理设计了分散控制律,并利用概率极限理论分析了闭环系统的稳定性和最优性.主要结果包括(1)证明了对种群状态的平均的估计在某种范数意义下的强一致性,即种群状态的平均与其估计值之间的误差在该范数意义下将随系统个体数N的增加几乎必然收敛于0;(2)证明了闭环系统的几乎必然一致稳定性,即系统的稳定性与种群个体数N无关;(3)证明了所设计的分散控制律是几乎必然渐近Nash均衡策略.     

A discontinuous Galerkin method for the Rosenau equation

A priori error estimates for the Rosenau equation, which is a K-dV like Rosenau equation modelled to describe the dynamics of dense discrete systems, have been studied by one of the authors. But since a priori error bounds contain the unknown solution and its derivatives, it is not effective to control error bounds with only a given step size. Thus we need to estimate a posteriori errors in order to control accuracy of approximate solutions using variable step sizes. A posteriori error estimates of the Rosenau equation are obtained by a discontinuous Galerkin method and the stability analysis is discussed for the dual problem. Numerical results on a posteriori error and wave propagation are given, which are obtained by using various spatial and temporal meshes controlled automatically by a posteriori error.     

Variable impulsive consensus of nonlinear multi-agent systems

In this paper, the consensus problem for nonlinear multi-agent systems with variable impulsive control method is studied. In order to decrease the communication wastage, a novel distributed impulsive protocol is designed to achieve consensus. Compared with the common impulsive consensus method with fixed impulsive instants, the variable impulsive consensus method proposed in this paper is more flexible and reliable in practical application. Based on Lyapunov stability theory and some inequality techniques, several novel impulsive consensus conditions are obtained to realize the consensus of multi-agent systems. Finally, some necessary simulations are performed to validate the effectiveness of theoretical results.