Distributed Time-Varying Formation Tracking Analysis and Design for Second-Order Multi-Agent Systems

Distributed time-varying formation tracking analysis and design problems for second-order multi-agent systems with one leader are studied respectively, where the states of followers form a predefined time-varying formation while tracking the state of the leader. Different from the previous results on formation tracking control, the formation for the followers can be described by specified time-varying vectors and the trajectory of the leader can also be time-varying. A distributed formation tracking protocol is constructed using only neighboring relative information. Necessary and sufficient conditions for second-order multi-agent systems with one leader to achieve time-varying formation tracking are proposed by utilizing the properties of the Laplacian matrix, where the formation tracking feasibility constraint is also given. An approach to design the formation tracking protocol is proposed by solving an algebraic Riccati equation. The presented results can be applied to deal with the target enclosing problems and consensus tracking problems for second-order multi-agent systems with one target/leader. An application in the target enclosing of multiple vehicles is provided to demonstrate the effectiveness of the theoretical results.     

Mean Square Bipartite Consensus for Multi-agent Systems with Measurement Noises and Communication Time-delays

International Journal of Control, Automation and Systems - This paper investigates the mean square bipartite consensus problem of a multi-agent system with considering measurement noises and...     

Designing Proportional-Integral Consensus Protocols for Second-Order Multi-Agent Systems Using Delayed and Memorized State Information

This paper is concerned with consensus of a secondorder linear time-invariant multi-agent system in the situation that there exists a communication delay among the agents in the network. A proportional-integral consensus protocol is designed by using delayed and memorized state information. Under the proportional-integral consensus protocol, the consensus problem of the multi-agent system is transformed into the problem of asymptotic stability of the corresponding linear time-invariant time-dela...     

Robust Consensus Tracking Control of Uncertain Multi-Agent Systems With Local Disturbance Rejection

In this paper, a new distributed consensus tracking protocol incorporating local disturbance rejection is devised for a multi-agent system with heterogeneous dynamic uncertainties and disturbances over a directed graph. It is of two-degree-of-freedom nature. Specifically, a robust distributed controller is designed for consensus tracking, while a local disturbance estimator is designed for each agent without requiring the input channel information of disturbances. The condition for asymptotic di...     

具有随机量测噪声的变结构控制

本文研究了一种考虑状态量测噪声的变结构控制，提出了随机超平面的概念。分别以随机噪声的导数有界与无界情况设计出了控制律，并估计出随机超平面的方差界。     

基于间歇事件触发控制二阶多智能体网络的一致性*

针对二阶多智能体网络在无向连通拓扑结构下的间歇控制一致性问题,引入了合适的事件触发控制算法,该算法能够有效的减少控制器的更新次数。同时,模型中的每个智能体具有非线性项,使得多智能体网络更为实际。采用Lyapunov-Krasovskii泛函方法,对网络进行了一致性分析,给出了事件触发控制算法下二阶多智能体网络趋于一致的充分条件,得到了网络通讯间隔的要求,并排除了Zeno现象。最后,数值仿真结果进一步验证了理论分析的正确性。     

带有通信时滞的二阶多智能体系统一致问题

针对具有双向等时延的二阶无向通信拓扑系统,采用带有通信时滞的线性一致控制率协议,分析了使系统稳定的条件。由于系统的阶次较高,直接对其特征方程进行分析是比较困难的,提出了一种新的分析方法,把系统的特征方程分解为多个子系统的乘积,然后利用CTCR方法,求得每个子系统对应的时滞最大值,比较后得出使系统达到一致稳定的最大时滞,作出了控制率边界曲线图并标出了稳定区域。结果表明,在有向生成树的情况下,当时滞小于决策值时,系统能达到稳定。最后,数值仿真验证了所得结果的有效性。     

具有时滞的二阶多智能体系统的一致性分析

多智能体系统是由多个自主的智能体组成的集合,实现协调合作的首要条件就是各个多智能体达到一致.本文应用频域分析法研究了具有时滞的二阶定拓扑多智能体系统的一致性问题,得到了保证所有智能体状态达到一致的充分必要条件,并且给出了系统最大容许时滞与定拓扑图的Laplacian矩阵特征值之间的关系.最后,通过数值仿真验证了所得结论的有效性.     

带虚拟领导者的多智能体系统的非光滑一致性

研究了在限制交互范围条件下具有一个虚拟领导者的二阶多智能体系统的一致性问题。假设多智能体系统中所有智能体均可以接收到领导者的信息，而智能体之间只有距离在一定范围内才可以进行相互通信。在相对状态反馈的线性一致性协议下，通过李雅普诺夫法，证明了该多智能体系统二阶一致性的充分条件。接着通过仿真实例验证了理论结果，并对该算法作出了总结。     

多智能体系统的非震颤固定时间一致性

研究了多智能体系统的非震颤固定时间一致性问题。基于李雅普诺夫稳定性理论,导出了实现固定时间一致性的充分条件,其中到达一致时间的上界估计不再依赖于多智能体系统的初始状态条件。此外,与传统含有符号函数的有限时间和固定时间控制器不同的是,所提出的新颖控制方案是非震颤的,有利于多智能体系统的一致性性能表征。最后,用一个数值例子验证了理论分析结果的有效性和可行性。     

具有有色噪声的线性随机系统的矩稳定性

研究具有有色噪声的线性随机系统的矩稳定性,得到了无需计算矩阵方根的矩阵特征值代数判据,并用实例演示了文中的方法。     

含通信延时及输入延时的线性多智能体的一致性

针对通信延时及输入延时并存的情况下,研究具有一般线性动态特性的高阶多智能体在固定且无向的网络拓扑下的一致性.通过将多智能体的特征方程分解为一系列低阶的因子,一致性问题转换为一系列低阶因子的稳定性分析问题,降低了问题的分析复杂度.进一步地,分析无延时情况下多智能体达到一致性的控制增益的取值范围,即增益的稳定区间.当从稳定区间选取一个固定的控制增益时,应用频率扫描高级聚类法分析多个因子在两延时参数空间中的稳定性,并由此获得多智能体延时无关及延时相关的一致性结论.一个说明性的例子验证了分析结论.     

具有时滞的混合阶多智能体系统的组一致性

针对由离散时间一阶和二阶智能体组成的混合阶多智能体系统,研究其在固定和切换拓扑结构下受通信时滞影响时的组一致性问题。分别为两类智能体提出组一致性协议,引入模型变换,将闭环系统转化为等价系统。在一定假设条件下,以代数图论、矩阵理论为主要研究工具,分别在固定和切换拓扑结构下给出了混合阶多智能体系统实现渐近组一致性的条件。采用数值仿真对所得结果的有效性进行了验证。     

Fixed-Time Output Consensus Tracking for High-Order Multi-Agent Systems With Directed Network Topology and Packet Dropout

This paper studies the problem of fixed-time output consensus tracking for high-order multi-agent systems(MASs)with directed network topology with consideration of data packet dropout.First,a predictive compensation based distributed observer is presented to compensate for packet dropout and estimate the leader’s states.Next,stability analysis is conducted to prove fixed time convergence of the developed distributed observer.Then,adaptive fixed-time dynamic surface control is designed to counteract mismatched disturbances introduced by observation error,and stabilize the tracking error system within a fixed time,which overcomes explosion of complexity problem and singularity problem.Finally,simulation results are provided to verify the effectiveness and superiority of the consensus tracking strategy proposed.The contribution of this paper is to provide a fixed-time distributed observer design method for high-order MAS under directed graph subject to packet dropout,and a novel fixed-time control strategy which can handle mismatched disturbances and overcome explosion of complexity and singularity problem.     

Event-Triggered Asymmetric Bipartite Consensus Tracking for Nonlinear Multi-Agent Systems Based on Model-Free Adaptive Control

In this paper, an asymmetric bipartite consensus problem for the nonlinear multi-agent systems with cooperative and antagonistic interactions is studied under the event-triggered mechanism. For the agents described by a structurally balanced signed digraph, the asymmetric bipartite consensus objective is firstly defined, assigning the agents’ output to different signs and module values. Considering with the completely unknown dynamics of the agents, a novel event-triggered model-free adaptive bipartite control protocol is designed based on the agents’ triggered outputs and an equivalent compact form data model. By utilizing the Lyapunov analysis method, the threshold of the triggering condition is obtained. Subsequently, the asymptotic convergence of the tracking error is deduced and a sufficient condition is obtained based on the contraction mapping principle. Finally, the simulation example further demonstrates the effectiveness of the protocol.      

Accuracy of Construction of Approximating Models under Bounded Measurement Noises

If the output of a system is measured under an additive noise with predefined set-valued estimate, then there is an optimal size for the vector of parameters of the approximating model under which the guaranteed approximation error is minimal. This result is extended to the case in which the a priori noise estimate depends on the measured parameter.__________Translated from Avtomatika i Telemekhanika, No. 5, 2005, pp. 125–133.Original Russian Text Copyright © 2005 by Kuntsevich.     

Group Hybrid Coordination Control of Multi-Agent Systems With Time-Delays and Additive Noises

A new kind of group coordination control problemgroup hybrid coordination control is investigated in this paper.The group hybrid coordination control means that in a whole multi-agent system(MAS) that consists of two subgroups with communications between them,agents in the two subgroups achieve consensus and containment,respectively.For MASs with both time-delays and additive noises,two group control protocols are proposed to solve this problem for the containment-oriented case and consensus-ori...     

Polynomial Design of Optimal Sampled-Data Tracking Systems I. Quadratic Optimization

A method of optimal design of digital tracking systems for continuous-time plants is presented. The method is based on the use of Laplace transformation in continuous time and polynomial equation theory. The cost function employed for quadratic optimization takes system performance in continuous time into account. The structure of optimal digital controller transfer function is investigated and its order is determined explicitly. The possibility of designing optimal tracking system for a neutral plant is analyzed.     

Aperiodic Sampled-Data Control of Distributed Networked Control Systems Under Stochastic Cyber-Attacks

This paper examines the stabilization problem of a distributed networked control system under the effect of cyber-attacks by employing a hybrid aperiodic triggering mechanism. The cyber-attack considered in the paper is a stochastic deception attack at the sensor-controller end. The probability of the occurrence of attack on a subsystem is represented using a random variable. A decentralized hybrid sampled-data strategy is introduced to save energy consumption and reduce the transmission load of the network. In the proposed decentralized strategy, each subsystem can decide independently whether its state should be transmitted to the controller or not. The scheme of the hybrid triggering mechanism for each subsystem composed of two stages: In the first stage, the next sampling instant is computed using a self-triggering strategy. Subsequently, in the second stage, an event-triggering condition is checked at these sampling instants and the control signal is computed only if the event-triggering condition is violated. The self-triggering condition used in the first stage is dependent on the selection of event-triggering condition of the second stage. Finally, a comparison of the proposed approach with other triggering mechanisms existing in the literature is presented in terms of the sampling instants, transmission frequency and performance measures through simulation examples.      

Consensus of Multi-Agent Systems With Diverse Input and Communication Delays

The consensus problem for multi-agent systems with input and communication delays is studied based on the frequency-domain analysis. Two decentralized consensus conditions are obtained, one of which is given for the systems based on undirected graphs with diverse input delays and the other is for the systems based on directed graphs with diverse communication delays and input delays. For the systems with both communication delays and input delays, the consensus condition is dependent on input delays but independent of communication delays.