Leader-following consensus for discrete-time multi-agent systems with parameter uncertainties based on the event-triggered strategy

In this paper, the leader-following consensus for discrete-time multi-agent systems with parameter uncertainties is investigated based on the event-triggered strategy. And the parameter uncertainty is assumed to be norm-bounded. A consensus protocol is designed based on the event-triggered strategy to make the multi-agent systems achieve consensus without continuous communication among agents. Each agent only needs to observe its own state to determine its own triggering instants under the triggering function in this paper. In addition, a sufficient condition for the existence of the event-triggered consensus protocol is derived and presented in terms of the linear matrix inequality. Finally, a numerical example is given to illustrate to efficiency of the event-triggered consensus protocol proposed in this paper.     

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.     

单边Lipschitz非线性多智能体系统一致性追踪控制

针对单边Lipschitz非线性多智能体系统,提出了一种分布式一致性控制方法.首先,构建了领导-跟随者动力学结构,用于实现单边Lipschitz多智能体系统的追踪控制.然后,设计了单边Lipschitz非线性多智能体系统的一致性控制协议,可根据智能体之间局部交互信息构建分布式反馈控制,并将系统的一致性追踪问题转化为系统...     

RHC-Based Consensus of Multi-Agent Systems with Simultaneous Packet Dropout and Input Delay

This paper is concerned with the multi-agent systems with both packet dropout and input delay. A novel receding horizon control (RHC) based consensus protocol is proposed by solving a distributed RHC based optimization problem. The novelty of the optimization problem lines in the involvement of the neighbours’ predictor information in the cost functions. Based on the derived RHC based consensus protocol, the necessary and sufficient condition for the mean-square consensus is obtained. In addition, the authors give a specific sufficient condition to guarantee the mean-square consensus.

     

Event-Triggered Sampled-Data Consensus of Nonlinear Multi-Agent Systems with Control Input Losses

This paper investigates the leader-following consensus problem for multi-agent systems with event-triggered mechanism and control packet losses. Based on the local synchronization error, event-triggered mechanisms are proposed in order to reduce the number of controller update. The control packet may lose due to unreliability of communication channel. With the assumption that once the packet loss happens the controller will be set to zero, sufficient consensus criteria for multi-agent system with event-triggered mechanism and control packet losses is obtained. It is also shown that the interplay among the allowable packet loss rate, event-triggered mechanism and sampling period. An illustrative example is given to demonstrate the effectiveness of the theoretical results.     

Robust consensus tracking of heterogeneous multi-agent systems under switching topologies

This paper considers a robust consensus tracking problem of heterogeneous multi-agent systems with time-varying interconnection topologies. Based on common Lyapunov function and internal model techniques, both state and output feedback control laws are derived to solve this problem. The proposed design is robust by admitting some parameter uncertainties in the multi-agent system.     

Adaptive Event-Triggering Consensus for Multi-Agent Systems with Linear Time-Varying Dynamics

In this paper, the authors study the fully distributed event-triggering consensus problem for multi-agent systems with linear time-varying dynamics, where each agent is described by a linear time-varying system. An adaptive event-triggering protocol is proposed for time-varying multi-agent systems under directed graph. Based on the Gramian matrix of linear time-varying systems, the design of control gain is done and sufficient conditions ensuring the consensus of linear time-varying multi-agent systems are obtained. It is shown that the coupling strength is closely related to the triggering condition. When it comes to undirected graph, it is shown that the coupling strength is independent on the triggering condition and thus the design procedure is of more freedom than the directed case. In addition, it is also proved that Zeno behaviours can be excluded in the proposed protocols. A numerical example is presented to demonstrate the effectiveness of the theoretical results.

     

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.     

Consensus of Linear Multi-Agent Systems with Persistent Disturbances via Distributed Output Feedback

This paper addresses the consensus problem of general linear multi-agent systems with persistent disturbances by distributed output feedback. Suppose that states of agents can not be obtained directly. Several estimators are designed to observe states of agents and the unknown disturbances.A protocol is proposed to drive all agents achieve consensus. Based on the method of model transformation and the property of permutation matrix, sufficient conditions for consensus are obtained in terms of linear matrix inequalities. Finally, simulations are given to show the effectiveness of presented results.     

基于MRPs的卫星集群系统姿态对抗一致性控制

小型卫星集群协同控制是当前空间技术发展的热点之一, 卫星集群控制可归结为多智能体控制问题。面向卫星集群系统的分组姿态控制, 引入一致性以及对抗一致性问题, 提出了卫星系统姿态对抗一致性控制方法。卫星组网系统姿态对抗一致性控制目标是使卫星分组达到姿态对称的状态。以无向图描述姿态对抗卫星集群的通讯拓扑结构, 利用修正型罗德里格斯参数方法描述卫星刚体运动姿态, 设计了一种基于多智能体协同控制理论的三维空间卫星集群姿态对抗一致性控制律, 并采用Lyapunov稳定性理论证明了其稳定性。最后, 通过仿真实验验证了所提方法的有效性。     

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.     

Bipartite Consensus of Linear Multi-Agent Systems by Distributed Event-Triggered Control

For multi-agent systems with competitive and collaborative relationships, signed graph can more intuitively express the characteristics of their interactive networks. In this paper, the bipartite consensus is investigated for multi-agent systems with structurally balanced signed graph. In order to reduce actuation burden in dynamical network environment, the event-triggering strategy is applied to bipartite consensus protocol for the multi-agent systems. The triggered condition for each agent is designed by using its own information and transmitted information of its neighbors at sampling instant and make the number of triggers of the whole systems be reduced. Based on the distributed eventtriggered control, some sufficient conditions are derived to guarantee the leaderless and leader-following bipartite consensus. Finally, some numerical examples are shown to demonstrate the effectiveness of the theoretical results.     

Observer-based event-triggered tracking control of leader-follower systems with time delay

This paper studies the tracking control of general linear multi-agent systems with or without time delays. The observer-based event-triggered control schemes will be considered. For the conventional distributed tracking protocol, the authors will not update the relative state in continuous time, i.e., the relative state will be updated by some events which happened in discrete time. A completely decentralized event-trigger will be designed for leader-follower systems. It is shown that all followers can track the leader asymptotically by the proposed protocol, if the feedback gain matrices are designed appropriately. Numerical simulations are also provided and the results show highly consistent with the theoretical results.     

基于观测器的时滞依赖鲁棒无源控制

研究一类带有参数不确定性和时变时滞的不确定线性系统的鲁棒无源控制问题。针对标称系统,利用线性矩阵不等式给出其时滞依赖无源性条件;讨论当系统的系数矩阵出现参数不确定时,存在基于观测器的控制器使得闭环系统是强鲁棒稳定且严格无源的时滞依赖性充分条件。构造出期望的观测器和控制器。数值算例说明结论的有效性。     

Time-Variant Consensus Tracking Control for Networked Planar Multi-Agent Systems with Non-Holonomic Constraints

A time-variant consensus tracking control problem for networked planar multi-agent systems with non-holonomic constraints is investigated in this paper. In the time-variant consensus tracking problem, a leader agent is expected to track a desired reference input, simultaneously, follower agents are expected to maintain a time-variant formation. To solve the time-variant consensus tracking problem of planar multi-agent systems with non-holonomic constraints, a time-variant consensus tracking control strategy is designed on the basis of an unidirectional topology structure. One of main contributions of this paper is the time-variant consensus tracking protocol for general time-variant formations of planar multi-agent systems with non-holonomic constraints, the other main contribution of this paper is an active predictive control strategy, where predictions of agents are generated actively, so that the computational efficiency is improved than passive approaches. The proposed control strategy is verified by two types of time-varying formations of wheeled mobile robots, and the experimental results show that the proposed control strategy is effective for general time-variant consensus tracking problems of planar multi-agent systems with non-holonomic constraints in local and worldwide networked environments.     

基于干扰估计的高超声速飞行器鲁棒控制方法

针对高超声速飞行器高度与速度跟踪所面临的参数不确定与外界干扰问题,提出基于干扰估计的鲁棒控制律设计方法。首先建立含参数不确定与外界干扰的高超声速飞行器模型;而后基于动态逆思想,将动力学模型进行线性化,并将由参数不确定与外界干扰对系统造成的总效果看作系统总干扰,从而引入线性扩张状态观测器实现对系统状态及总干扰的估计;最后考虑总干扰作用,提出具有鲁棒性能的动态逆控制律与滑模控制律。通过与传统控制律进行对比仿真,结果表明所设计的两种鲁棒控制器只需在原有方法基础上进行简单改进,即可较大程度提高对系统参数不确定与外界干扰的鲁棒性,具有良好的跟踪性能。     

不确定广义系统的保成本可靠控制

对一类含有时变范数有界参数不确定广义系统和部分执行器可能失效的系统,结合一个二次型性能指标,研究了使得闭环系统保持正则、无脉冲和稳定,且闭环性能指标值不超过某个确定界的保成本可靠控制律的设计问题。通过矩阵不等式导出保成本可靠控制律的一个充分存在条件,进而用线性矩阵不等式给出了保成本可靠控制器的一个参数化的表示。在此基础上,通过建立并求解一个凸优化问题,给出了最优保成本可靠控制律的设计方法。最后,通过例子对所得结论加以说明。     

Mean Square Average Generalized Consensus of Multi-Agent Systems Under Time-Delays and Stochastic Disturbances

Compared with the traditional consensus problem, this paper deals with the mean square average generalized consensus(MSAGC) of multi-agent systems under fixed directed topology, where all agents are affected by stochastic disturbances. Distributed protocol depending on delayed time information from neighbors is designed. Based on Lyapunov stability theory, together with results from matrix theory and It o s derivation theory, the linear matrix inequalities approach is used to establish sufficient conditions to ensure MSAGC of multi-agent systems. Finally, numerical simulations are provided to illustrate the theoretical results.     

Decentralized robust guaranteed cost control for a class of interconnected singular large-scale systems with time-delay and parameter uncertainty

The decentralized robust guaranteed cost control problem is studied for a class of interconnected singular large-scale systems with time-delay and norm-bounded time-invariant parameter uncertainty under a given quadratic cost performance function. The problem that is addressed in this study is to design a decentralized robust guaranteed cost state feedback controller such that the closed-loop system is not only regular, impulse-free and stable, but also guarantees an adequate level of performance for all admissible uncertainties. A sufficient condition for the existence of the decentralized robust guaranteed cost state feedback controllers is proposed in terms of a linear matrix inequality (LMI) via LMI approach. When this condition is feasible, the desired state feedback decentralized robust guaranteed cost controller gain matrices can be obtained. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed approach.     

线性不确定系统的鲁棒容错H∞控制设计

研究了线性不确定系统的鲁棒容错H∞控制问题.当系统既有状态滞后,又有控制输入滞后,而且状态和控制输入的不确定项均满足匹配条件时,运用线性矩阵不等式(LMI)方法,提出了一种针对不确定系统的鲁棒容错反馈控制设计方法.利用该方法设计的闭环系统,不仅在传感器发生故障时具有完整性,而且对于系统的参数不确定性具有鲁棒性.以设计实例及仿真结果验证了这种方法的有效性.