Cooperative output regulation of heterogeneous multi-agent systems based on passivity

This paper investigates the problem of cooperative output regulation of heterogeneous linear multi-agent systems. A passive framework is presented for the stabilisation analysis of cooperative output regulation, which can overcome the difficulty caused by the fact that the global dynamics of heterogeneous multi-agent systems depends on the global communication structure. An adaptive distributed observer is proposed to estimate the state of the exosystem, and the proposed distributed observer is independent of any global information of the communication graph. Based on passivity design and adaptive distributed observer, both a distributed state feedback and a distributed output feedback protocol are designed for output synchronisation of heterogeneous multi-agent systems. The gain matrices of the distributed protocols and observers are obtained by a Riccati equation design approach. Furthermore, sufficient local conditions for solving the problem of cooperative output regulation of heterogeneous multi-agent systems are presented. Finally, numerical simulation results are given to illustrate the effectiveness of the proposed distributed control schemes.     

Leader-following fixed-time output feedback consensus for second-order multi-agent systems with input saturation

This paper investigates the leader-following fixed-time output feedback consensus problem for second-order multi-agent systems with input saturation. By combing fixed-time control technique and bi-limit homogeneous systems theory, a class of bounded fixed-time consensus protocols are developed for leader-following multi-agent systems. The protocol design is divided into two parts. First, when all the state information of the followers are measurable, a state feedback consensus protocol is designed to achieve fixed-time consensus. Then, when the velocity information is unmeasurable, an observer-based fixed-time consensus protocol is proposed. With the help of Lyapunov stability theorem and the property of a homogeneous function, it is theoretically shown that the states of all followers can track that of the leader in fixed-time in the presence of input saturation. Finally, numerical simulation is carried out to illustrate the effectiveness of theoretical results.     

线性多智能体系统在固定和切换拓扑下的领航跟随控制

研究线性多智能体系统的领航跟随一致性问题. 假设每个多智能体系统只能得到其邻域的输出测量信息, 在此条件下, 讨论多智能体在有向固定网络拓扑和无向切换网络拓扑两种情况下的一致性问题. 针对这两种情况, 提出含有一种分布式观测器的一致性控制算法. 应用Lyapunov 稳定性理论证明了若单个多智能体系统是可镇定和可检测的, 且网络连接拓扑只需满足简单的结构, 则系统能够达到领航跟随一致性. 仿真结果验证了理论分析的正确性.     

Cooperative output regulation with application to multi-agent consensus under switching network

In this paper, we consider the cooperative output regulation of linear multi-agent systems under switching network. The problem can be viewed as a generalization of the leader-following consensus problem of multi-agent systems. Due to the limited information exchanges of different subsystems, the problem cannot be solved by the decentralized approach and is not allowed to be solved by the centralized control. By devising a distributed observer network, we can solve the problem by both dynamic state feedback control and dynamic measurement output feedback control. As an application of our main result, we show that a special case of our results leads to the solution of the leader-following consensus problem of linear multi-agent systems.     

拒绝服务攻击下领导-跟随多智能体系统的均方一致性研究

针对带有过程噪声和测量噪声的领导-跟随多智能体系统,研究拒绝服务攻击下多智能体系统的一致性问题.首先,设计基于卡尔曼滤波的状态观测器,对智能体状态进行有效准确的估计;然后,基于预测控制理论提出一种基于状态估计信息的分布式预测控制算法,从而实现领导-跟随多智能体系统的均方一致性控制,并给出拒绝服务攻击环境下实现领导-跟随多智能体系统均方一致性的充分必要条件;最后,通过数值仿真验证所提出方法的正确性和有效性.     

Event-triggered distributed containment control of heterogeneous linear multi-agent systems by an output regulation approach

In this paper, the event-triggered distributed containment control of heterogeneous linear multi-agent systems in the output regulation framework is studied. The leaders are treated as exosystems and the containment control problem will be converted into an output regulation problem. An event-triggered protocol is then designed for each follower by the output information of neighbours. It is proved that the followers can asymptotically converge to the dynamic convex hull spanned by multiple leaders under the designed protocol and triggered strategy. Furthermore, it is shown that the proposed protocol and triggered condition can exclude Zeno behaviour, so the feasibility of the control strategy is verified. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed protocol.     

带有不连续动力学的非线性多智能体系统固定时间一致性EI北大核心CSCD

本文研究了一类带有不连续动力学和有界扰动的非线性多智能体系统领导跟随固定时间一致性问题.首先,在不对称的有向拓扑图下,本文设计了一种辅助信号,该辅助信号用于观测领导者状态,且该辅助信号不在通信信道中传输,可以有效地减少系统计算代价.随后,基于辅助信号,本文设计了一种不连续控制协议,以实现多智能体系统固定时间收敛.然后,利用非光滑分析、Lyapunov稳定性理论及代数图论等证明系统可在任意初始状态下达到固定时间一致.最后,仿真实例进一步验证了理论结果的有效性.     

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.     

Consensus control of leader-following nonlinear multi-agent systems with distributed adaptive iterative learning control

This paper addresses the consensus problem of leader-following nonlinear multi-agent systems with iterative learning control. The assumption that only a small portion of following agents can receive the information of leader agent is considered. To approximate the nonlinear dynamics of a given system, the radial basis function neural network is introduced. Then, a distributed adaptive iterative learning control protocol with an auxiliary control term is designed, where the estimates of nonlinear dynamics are applied in control protocol design and three adaptive laws are presented. Furthermore, the convergence of the proposed control protocol is analysed by Lyapunov stability theory. Finally, a simulation example is provided to demonstrate the validity of theoretical results.     

网络环境下固定拓扑的多电机领航跟随控制

基于多智能体一致性理论,从领航跟随控制的角度解决网络环境下多电机的同步控制问题,其中考虑了网络时延对同步控制的影响。每个电机均被视为一个智能体,且每个智能体能且只能得到其邻域的输出测量信息,在此条件下,研究了在有向固定网络拓扑情况下多电机系统的同步控制问题。为了解决网络时延对电机同步控制的影响,提出了一种带有分布式观测器的时延一致性控制协议,应用 Lyapunov稳定性理论证明了若单个电机是能观能控的,只要网络连接满足简单的拓扑结构,则多电机系统能够达到领航跟随一致性。最后通过仿真实验验证了该方法的正确性和有效性。     

Leader-following consensus of fractional-order multi-agent systems via adaptive pinning control

In this paper, the leader-following consensus problem of fractional-order multi-agent systems is considered via adaptive pinning control. The dynamics of leader and all followers with linear and nonlinear functions are investigated, respectively. We assume that the node should be pinned if its in-degree is less than its out-degree in the paper. Under this assumption and based on the stability theory of fractional-order differential systems, some leader-following consensus criteria are derived, which are easily obtained by matrix inequalities. The control of each agent using local information is designed and detailed analysis of the leader-following consensus is presented. The design technique is based on algebraic graph theory and the Riccati inequality. Several simulation examples are presented to demonstrate the effectiveness of the proposed method.     

A Continuous Leader-following Consensus Control Strategy for a Class of Uncertain Multi-agent Systems

In this paper, we study the robust leader-following consensus problem for a class of multi-agent systems with unknown nonlinear dynamics and unknown but bounded disturbances. The control input of the leader agent is nonzero and not available to any follower agent. We first consider a class of high order chain integrator-type multi-agent systems. By employing the robust integral of the sign of the error technique, a continuous distributed control law is constructed using local information obtained from neighboring agents. Using Lyapunov analysis theory, we show that under a connected undirected information communication topology, the proposed protocol achieves semiglobal leader-following consensus. We then extend the approach to a class of more general uncertain multiagent systems. A numerical example is given to verify our proposed protocol.      

Second-order leader-following consensus based on time and event hybrid-driven control

The leader-following consensus problem of multi-agent systems with double-integrator dynamics is considered in this paper. Herein, there is only one leader, the interaction topology among the followers is undirected, and the followers are reachable from the leader. A novel consensus protocol based on time and edge event hybrid-driven techniques is proposed, and two associated event-triggering rules are presented. Each edge event relies on the information of the corresponding two neighboring agents and event-triggering actions over different edges are independent of each other. It is shown that the proposed protocol can solve the leader-following consensus problem. Moreover, the controller-updating costs and communication costs are largely reduced. Finally, simulations are given to demonstrate the effectiveness of our theoretical results.     

高阶有向积分器网络的包含控制

研究高阶固定有向积分器网络的包含控制问题。针对静止和运动的领导者,分别为跟随者提出了不同的控制协议。领导者是静止的情况下,应用拉普拉斯变换终值定理提出线性控制协议,驱使跟随者渐近进入由多个领导者所构成的静态凸包中;领导者是移动的情况下,提出非线性控制协议,以保证跟随者能够渐近进入由多个领导者所构成的动态凸包中,并使跟随者一直保持在该凸包中,同时提出了能够达到这一目标的充分条件。仿真结果验证了该理论分析的正确性。     

A Novel Leader-following Consensus of Multi-agent Systems with Smart Leader

This article studies the leader-following consensus problem for mixed-order multi-agent systems with a leader. Different from the traditional leader which is independent of all the other agents, the leader, called smart leader, can obtain and utilize the feedback information from its neighbors at some disconnected time intervals. A new distributed consensus control protocol based on intermittent control is developed for leader-following consensus with a smart leader. Moreover, the smart leader can adjust the control protocol based on the feedback information from its neighbors. With the aid of Lyapunov function, some sufficient conditions are derived for leader-following consensus of multi-agent systems with mixed-order dynamics under fixed directed topology. In addition, the similar results are obtained under switching directed topology. Finally, simulation results are provided to verify the correctness and effectiveness of theoretical results.     

Prescribed performance global stable adaptive neural dynamic surface consensus tracking control of stochastic multi-agent systems with hysteresis inputs and nonlinear dynamics

This paper focuses on the leader-following consensus control problem of stochastic multi-agent systems with hysteresis inputs and nonlinear dynamics. A leader-following consensus scheme is presented for stochastic multi-agent systems directions under directed graphs, which can achieve predefined synchronisation error bounds. By mainly activating an auxiliary robust control component for pulling back the transient escaped from the neural active region, a multi-switching robust neuro adaptive controller in the neural approximation domain, which can achieve globally uniformly ultimately bounded tracking stability of multi-agent systems recently. A specific Nussbaum-type function is introduced to solve the problem of unknown control directions. Using a dynamic surface control technique, distributed consensus controllers are developed to guarantee that the outputs of all followers synchronise with that of the leader with prescribed performance. Based on Lyapunov stability theory, it is proved that all signals in closed-loop systems are uniformly ultimately bounded and all the follower agents can keep consensus with the leader. Two simulation examples are provided to illustrate the effectiveness and advantage of the proposed control scheme.     

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.     

事件触发机制下的多智能体领导跟随一致性

研究了一类具有动态领导者的一阶多智能体系统的一致性问题。基于事件触发机制给出两种一致性协议,即集中式触发控制协议和分散式触发控制协议。利用李雅普诺夫稳定性理论和模型转化方法分别给出多智能体系统在两种协议作用下达到领导跟随一致的充分条件。同时,理论计算表明,系统在两种控制协议下均不存在Zeno行为。实例仿真结果验证了理论方案的有效性。     

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.     

Theory and Experiments on Enclosing Control of Multi-Agent Systems

This paper proposes a control strategy called enclosing control. This strategy can be described as follows: the followers design their control inputs based on the state information of neighbor agents and move to specified positions. The convex hull formed by these followers contains the leaders. We use the single-integrator model to describe the dynamics of the agents and proposes a continuous-time control protocol and a sampled-data based protocol for multi-agent systems with stationary leaders with fixed network topology. Then the state differential equations are analyzed to obtain the parameter requirements for the system to achieve convergence. Moreover, the conditions achieving enclosing control are established for both protocols. A special enclosing control with no leader located on the convex hull boundary under the protocols is studied, which can effectively prevent enclosing control failures caused by errors in the system. Moreover, several simulations are proposed to validate theoretical results and compare the differences between the three control protocols. Finally, experimental results on the multi-robot platform are provided to verify the feasibility of the protocol in the physical system.