Output regulation for linear multi-agent systems with unmeasurable nodes

The output regulation of linear multi-agent systems with partial unmeasurable agents is investigated in this paper. All the agents except the exosystem can be classified into two groups. Agents in the first group can be measured by themselves and their neighbors. State variables are not fully accessible for direct communication and full order Luenberger observers are constructed for the unmeasurable agents. We give a state feedback control law to solve the output regulation problem under the communication topologies based on both measurable and unmeasurable agents. The heterogeneous agents’ synchronization problem is a general case of our results. Finally, examples are utilized to show the effectiveness of the obtained results.     

Leaderless and leader-following consensus of linear multi-agent systems

This paper studies the consensus problems for multi-agent systems with general linear and nonlinear dynamics. The leaderless and leader-following consensus problems are investigated respectively. Contraction theory is employed to generate some sufficient conditions for testing the agents reaching consensus. Under these conditions and certain assumptions,the trajectories of multi-agent systems in directed topology will converge to each other. Finally, two numerical examples are given to illustrate the effectiveness of the proposed results.     

Agreement coordination for second-order multi-agent systems with disturbances

This paper is devoted to the study of consensus problems for the second-order multi-agent systems with external disturbances, switching topology and communication time-delay. Firstly, we perform a model transformation and separate the agreement states from the disagreement states. Secondly, according to this system, we derive a sufficient condition for consensus problem without disturbances by using the Lyapunov-based approach. Furthermore, we give a design criterion in terms of bilinear matrix inequality for the control protocol in the presence of disturbances. Finally, numerical simulations are provided to show the effectiveness of our strategies.     

Time-varying formation for general linear multi-agent systems via distributed event-triggered control under switching topologies

This paper investigates the time-varying formation problem for general linear multi-agent systems using distributed event-triggered control strategy.Different from the previous works,to achieve the desired time-varying formation,a distributed control scheme is designed in an event-triggered way,in which for each agent the controller is triggered only at its own event times.The interaction topology among agents is assumed to be switching.The common Lyapunov function as well as Riccati inequality is applied to solve the time-varying formation problem.Moreover,the Zeno behavior of triggering time sequences can be excluded for each agent.Finally,a simulation example is presented to illustrate the effectiveness of the theoretical results.     

Consensus for second-order multi-agent systems with position sampled data

In this paper, the consensus problem with position sampled data for second-order multi-agent systems is investigated.The interaction topology among the agents is depicted by a directed graph. The full-order and reduced-order observers with position sampled data are proposed, by which two kinds of sampled data-based consensus protocols are constructed. With the provided sampled protocols, the consensus convergence analysis of a continuous-time multi-agent system is equivalently transformed into that of a discrete-time system. Then, by using matrix theory and a sampled control analysis method, some sufficient and necessary consensus conditions based on the coupling parameters, spectrum of the Laplacian matrix and sampling period are obtained. While the sampling period tends to zero, our established necessary and sufficient conditions are degenerated to the continuous-time protocol case, which are consistent with the existing result for the continuous-time case. Finally, the effectiveness of our established results is illustrated by a simple simulation example.     

Consensus protocol for multi-agent continuous systems

Based on the algebraic graph theory, the networked multi-agent continuous systems are investigated. Firstly, the digraph （directed graph） represents the topology of a networked system, and then a consensus convergence criterion of system is proposed. Secondly, the issue of stability of multi-agent systems and the consensus convergence problem of information states are all analysed. Furthermore, the consensus equilibrium point of system is proved to be global and asymptotically reach the convex combination of initial states. Finally, two examples are taken to show the effectiveness of the results obtained in this paper.     

Finite-time information consensus for multi-agent systems with fixed and switching topologies

In this paper, we study the consensus problems for a group of interacting agents. First, we analytically establish the explicit expression of the consensus state for the entire group. Second, we prove that the agents of the group under a particular type of nonlinear interaction can reach the consensus state in finite time in the scenarios with fixed and switching undirected topologies. The results are also extended to the case where the topology of the group is directed and satisfies a detailed balance condition on coupling weights. Third, some numerical examples are provided to analyze the influencing factors of the convergence time, that is, the parameter of the particular interaction function and the algebraic connectivity of graphs. Finally, an application of the theoretical results in sensor networks is given, namely, computing the maximum-likelihood estimate of unknown parameters.     

Consensus problems of multi-agent systems with noise perturbation

In this paper, by using the stability theory of stochastic differential equations, the average-consensus problem with noise perturbation is investigated. It is analytically proved that the consensus could be achieved with a probability of one. Furthermore, numerical examples are taken to illustrate the effectiveness of the theoretical result.     

Consensus of compound-order multi-agent systems with communication delays

In complex environments, many distributed networked systems can only be illustrated with fractional-order dynamics. When multi-agent systems show individual diversity with difference agents, heterogeneous (integer-order and fractional-order) dynamics are used to illustrate the agent systems and compose integerfractional compounded-order systems. Applying Laplace transform and frequency domain theory of the fractional-order operator, the consensus of delayed multi-agent systems with directed weighted topologies is studied. Since an integer-order model is the special case of a fractional-order model, the results in this paper can be extended to systems with integer-order models. Finally, numerical examples are used to verify our results.     

时延多智能体系统分组一致性分析

研究了拓扑结构为连通无向图与连通二分图的一阶时延多智能系统分别在两类控制协议下的分组一致性问题．基于广义Nyquist准则与频域控制理论的方法,分析并得到了多智能体系统渐进分组收敛一致的充分条件．通过该条件发现系统分组一致性的达到与系统的时延以及智能体间的耦合强度相关．同时,时延的大小影响着系统的收敛速度与动态性能．仿真实验的结果进一步验证了理论分析所得结论的正确性．     

带时延与丢包的网络化多智能体系统控制器设计

网络时延与数据丢包极大地降低了网络化多智能体系统的控制性能,甚至会破坏稳定性.考虑存在网络时延与数据丢包的网络化多智能体系统,提出了一种基于时延与丢包补偿机制的预测控制器设计方法,来主动地消除网络时延与数据丢包的影响.通过对网络化多智能体预测控制系统的分析,给出了能够保证系统稳定性与一致性的控制器设计步骤.最后的仿真实例表明了该方法的有效性.     

Leader-following coordination of multi-agent systems with coupling time delays

In this paper, we consider a leader-following consensus problem of a group of autonomous agents with time-varying coupling delays. Two different cases of coupling topologies are investigated. At first, a necessary and sufficient condition is proved in the case when the interconnection topology is fixed and directed. Then a sufficient condition is proposed in the case when the coupling topology is switched and balanced. Numerical examples are also given to illustrate our results.     

Consensus of second-order multi-agent systems with nonuniform time delays

In this study, the consensus problem for a class of second-order multi-agent systems with nonuniform time delays is investigated. A linear consensus protocol is used to make all agents reach consensus and move with a constant velocity. By a frequency-domain analysis, a simplified sufficient condition is given to guarantee the consensus stability of the dynamic system. Finally, the effectiveness of the obtained theoretical results is illustrated through numerical simulations.     

Consensus of second-order multi-agent dynamic systems with quantized data

The consensus problem of second-order multi-agent systems with quantized link is investigated in this Letter. Some conditions are derived for the quantized consensus of the second-order multi-agent systems by the stability theory. Moreover, a result characterizing the relationship between the eigenvalues of the Laplacians matrix and the quantized consensus is obtained. Examples are given to illustrate the theoretical analysis.     

Consensus problems in multi-agent systems with double integrator model

In this paper, we consider multi-agent consensus problems in a decentralised fashion. The interconnection topology graph among the agents is switching and undirected. The agent dynamics is expressed in the form of a double integrator model. Two different cases are considered in this study. One is the leader-following case and the other is leaderless case. Based on graph theory and common Lyapunov function method, some sufficient conditions are obtained for the consensus stability of the considered systems with the neighbour-based feedback laws in both leader-following case and leaderless case respectively. Finally, two numerical examples are given to illustrate the obtained results.     

Leader-following consensus criteria for multi-agent systems with time-varying delays and switching interconnection topologies

We consider multi-agent systems with time-varying delays and switching interconnection topologies.By constructing a suitable Lyapunov-Krasovskii functional and using the reciprocally convex approach,new delay-dependent consensus criteria for the systems are established in terms of linear matrix inequalities(LMIs),which can be easily solved by using various effective optimization algorithms.Two numerical examples are given to illustrate the effectiveness of the proposed methods.     

Collective composite-rotating consensus of multi-agent systems

This paper investigates a distributed composite-rotating consensus problem of second-order multi-agent systems, where all agents move in a nested circular orbit. A distributed control law is proposed which contains two parts： the local state feedback that guarantees the circular motion and the distributed relative state feedback that guarantees the consensus of all agents. A sufficient condition is derived to drive all agents as well as ensure their circle centers make circular motion in a distributed manner. Finally, a numerical simulation is included to demonstrate our theoretical results.     

State-dependent event-triggered control of multi-agent systems

Event-triggered control has been recent/y proposed as an effective strategy for the consensus of multi-agent systems. We present an improved distributed event-triggered control scheme that remedies a shortcoming of some previous event- triggered control schemes in the literature. This improved distributed event-triggered method has no need for continuously monitoring each agent＇ neighbors. Moreover, each agent in the multi-agent systems will not exhibit the Zeno behavior. Numerical simulation results show the effectiveness of the proposed consensus control.     

Generation of optimal persistent formations for heterogeneous multi-agent systems with a leader constraint

In this study, we consider the generation of optimal persistent formations for heterogeneous multi-agent systems,with the leader constraint that only specific agents can act as leaders. We analyze three modes to control the optimal persistent formations in two-dimensional space, thereby establishing a model for their constrained generation. Then, we propose an algorithm for generating the optimal persistent formation for heterogeneous multi-agent systems with a leader constraint(LC-HMAS-OPFGA), which is the exact solution algorithm of the model, and we theoretically prove its validity.This algorithm includes two kernel sub-algorithms, which are optimal persistent graph generating algorithm based on a minimum cost arborescence and the shortest path(MCA-SP-OPGGA), and the optimal persistent graph adjusting algorithm based on the shortest path(SP-OPGAA). Under a given agent formation shape and leader constraint, LC-HMAS-OPFGA first generates the network topology and its optimal rigid graph corresponding to this formation shape. Then, LC-HMASOPFGA uses MCA-SP-OPGGA to direct the optimal rigid graph to generate the optimal persistent graph. Finally, LCHMAS-OPFGA uses SP-OPGAA to adjust the optimal persistent graph until it satisfies the leader constraint. We also demonstrate the algorithm, LC-HMAS-OPFGA, with an example and verify its effectiveness.