General Linear Multi-agent Systems Research Articles

Observer-based event-triggered time-varying formation control of linear multi-agent systems with distributed infinite delays

Compared with bounded delays, distributed infinite delays are more general in practical systems. Event-triggered control can effectively reduce energy consumption and communication costs. This paper addresses time-varying formation control of general linear multi-agent systems with distributed infinite delays in both of their inputs and outputs. An observer-based event-triggered formation control protocol considering distributed infinite delays is proposed, which is related to the combined observed information and some formation compensation signals at triggering time instants. By utilizing inequality techniques, the desired time-varying formation can be implemented while Zeno-behavior is excluded. Some numerical simulations are carried out for demonstrating the validity of theoretical results.

Secure Fully Distributed Event-Triggered Consensus of Multi-Agent Systems Against Distributed Sequential Scaling Attacks

This article is concerned with the secure fully distributed event-triggered consensus problem of general linear multi-agent systems subject to distributed sequential scaling (DSS) attacks. First, a generic DSS attack model is proposed, which enables different attack strategies in terms of scaling factors, attack frequency and duration to be incorporated in various communication channels. Different from existing attack models, the DSS attack is a kind of scaling attacks in which attack sequences are characterized by the sequential attacks and with distributed attack strategies for different attack objectives. To resist the adverse effects of such DSS attacks and further reduce the unnecessary communication consumption of each communication channel, a channel-based dynamic event-triggered mechanism is next presented. Moreover, a fully distributed event-triggered consensus control protocol is developed such that the dependence of any global information of the network topology can be eliminated. Formal analysis criteria on the asymptotic convergence of the resultant consensus errors and Zeno-freeness are then derived, where the relationship of the triggering parameters, distributed scaling factors and attack constraints is explicitly expressed. Furthermore, an offline algorithm without any global information is provided to determine both the adaptive consensus protocol gain matrices and the triggering parameters. Therefore, the parameters calculated by this algorithm are applicable to multi-agent systems of different scales, which also confirms the flexibility and scalability of the proposed fully distributed event-triggered consensus control protocol. Finally, two simulation examples involving different scales of intelligent vehicles are given to validate the efficacy of the obtained theoretical results.

Specified-Time Practical Consensus for General Linear Multi-Agent Systems With Switching Mechanism

Specified-Time Practical Consensus for General Linear Multi-Agent Systems With Switching Mechanism

Fully Distributed Algorithms for Constrained Nonsmooth Optimization Problems of General Linear Multiagent Systems and Their Application

Fully Distributed Algorithms for Constrained Nonsmooth Optimization Problems of General Linear Multiagent Systems and Their Application

Distributed Dynamic Event-Triggered Consensus Protocol for General Linear Multiagent Systems Without Accurate System Information.

This study focuses on distributed event-triggered consensus control under the scenario where only inaccurate agent model information is available. By designing a novel triggering error, a distributed dynamic event-triggered consensus (DETC) protocol is proposed for multiagent systems (MASs) with general linear dynamics over digraphs, without accurate a priori information of agent models. To improve the efficiency of the dynamic triggering law, a mixed triggering threshold is designed with a resilient function integrated to further enlarge interevent intervals. Within the proposed DETC protocol, the computational cost is significantly reduced especially for MASs with nonsparse and high-dimensional agent system matrices. In addition, for each individual agent, the states of neighboring agents used for triggering detections or controller updates are required in an on-demand (instead of continuous) way, which preserves communication resources and facilitates practical implementation. The feasibility of the designed DETC protocol is corroborated by rigorous theoretical analysis on consensus convergence and Zeno behavior exclusion. Finally, simulations are shown to demonstrate the effectiveness of the studied theory.

Optimal Consensus Control for Continuous-Time Linear Multiagent Systems: A Dynamic Event-Triggered Approach.

This article investigates the optimal consensus problem for general linear multiagent systems (MASs) via a dynamic event-triggered approach. First, a modified interaction-related cost function is proposed. Second, a dynamic event-triggered approach is developed by constructing a new distributed dynamic triggering function and a new distributed event-triggered consensus protocol. Consequently, the modified interaction-related cost function can be minimized by applying the distributed control laws, which overcomes the difficulty in the optimal consensus problem that seeking the interaction-related cost function needs all agents' information. Then, some sufficient conditions are obtained to guarantee optimality. It is shown that the developed optimal consensus gain matrices are only related to the designed triggering parameters and the desirable modified interaction-related cost function, relaxing the constraint that the controller design requires the knowledge of system dynamics, initial states, and network scale. Meanwhile, the tradeoff between optimal consensus performance and event-triggered behavior is also considered. Finally, a simulation example is provided to verify the validity of the designed distributed event-triggered optimal controller.

Fixed-time Consensus Control of General Linear Multi-agent Systems

Fixed-time Consensus Control of General Linear Multi-agent Systems

Composite Output Consensus Control for General Linear Multiagent Systems With Heterogeneous Mismatched Disturbances

Composite Output Consensus Control for General Linear Multiagent Systems With Heterogeneous Mismatched Disturbances

Fully distributed consensus of linear multi-agent systems via dynamic event-triggered control

This paper investigates the fully distributed consensus control problem for general linear multi-agent systems via dynamic event-triggered scheme. To address the need to reduce network communication burdens and avoid involving any global features of multi-agent networks, a novel fully distributed controller based on the open-loop state estimator of agents is presented. To improve anti-interference ability and practicability of the proposed approach, an event-triggered strategy which can guarantee a precise lower bound of triggering intervals for each follower is designed with a virtual internal variable. Then, the stability of the multi-agent systems is analyzed without any global network information. Several simulation experiments are conducted to illustrate theoretical results.

Human-in-the-Loop Formation-Containment Control for Multiagent Systems: An Observer-Based Distributed Unknown Input Reconstruction Method

This paper studies the human-in-the-loop time-varying formation-containment tracking (TVFCT) control problem of general linear multiagent systems (MASs). The MASs consist of a non-autonomous tracking leader, multiple formation leaders and followers, and all agents are subject to unknown disturbances. A human operator is deployed to supervise and regulate the entire team by sending a command signal to the tracking leader. The control input of the tracking leader should be combined with the human operator but not available to other agents. First, a local observer associated with each agent is constructed to provide asymptotic state estimation, in which the observer error system is disturbance-free. Also, interval observers are established for the neighborhood TVFCT errors, where the disturbance of the current agent is aggregated with the disturbances and input signals of its neighbors into an unknown input. Meanwhile, a distributed asymptotic unknown input reconstruction (UIR) mechanism is proposed that decouples the control input of the current agent. The consequent human-in-the-loop TVFCT control protocol is designed by combining the local observer and distributed UIR scheme. Finally, the theoretical results are verified in multi-robot formation-containment control.

Free-Weighting Matrix Approach for Event-Triggered Cooperative Control of Generic Linear Multi-agent Systems: An Application for UAVs

Free-Weighting Matrix Approach for Event-Triggered Cooperative Control of Generic Linear Multi-agent Systems: An Application for UAVs

The Binary Distributed Observer Approach to the Cooperative Output Regulation of Linear Multiagent Systems

In this note, the cooperative output regulation problem of general heterogeneous linear multi-agent systems with binary constraints is studied. To speed up the convergence rate, the binary distributed observer is proposed only utilizing sign of the relative state instead of using full relative information. Under some mild conditions, the binary distributed observer can estimate the state of the leader system exponentially in finite time sense. The leader system can generate various reference signals such as step functions, sinusoidal functions or their combinations. Furthermore, both state and output feedback control protocols are synthesized to solve the problem. An illustrative example is presented to support the feasibility of the proposed framework.

A fully distributed event-Triggered control approach to leader-following consensus of multiagent systems

This paper investigates the leader-following consensus problem for general linear multiagent systems under a fully distributed manner. To avoid using the global information of the communication network, two node-based adaptive parameters are designed and introduced to the fully distributed event-based control law. Such a protocol is more scalable and flexible for large-scaled and complex networked system, such as microgrids or multiple unmanned vehicles. A novel event-triggered rule is presented, and an internal dynamic variable is introduced in it to further cut down the triggering times and save the communication resources. A well-designed Lyapunov function candidate is constructed to not only ensure the convergence of the close-looped systems but also avoid using the eigenvalue of Laplacian matrix in the dynamic variable. Moreover, it is proved that the designed event-triggered conditions can avoid the Zeno behaviour. Finally, a simulation example based on a group of unmanned intelligent vehicle systems is provided to demonstrate the validity of the designed control method.

Secure Consensus of Multiagent Systems With DoS Attacks via Fully Distributed Dynamic Event-Triggered Control

This article investigates the secure consensus problem of general linear multiagent systems with denial-of-service (DoS) attacks. Owning to the existence of DoS attacks, it is challenging to investigate the event-triggered control of multiagent systems in a fully distributed manner. This article presents a novel dynamic event-triggered mechanism to alleviate the limited communication resources. Moreover, the designed mechanism is fully distributed and scalable owing to the introduction of some adaptive coupling weights. Since the DoS attacks have been considered in the event-triggered rule design, a novel adaptive parameter with an additional exponential term is adopted to deal with DoS attacks. The Lyapunov design also introduces such a term for the subsequent stability analysis. Sufficient conditions guaranteeing the asymptotic consensus of the studied system are developed in light of the controller’s parameters, duration, and frequency of the DoS attacks. Strict proof is provided to demonstrate that a secure consensus can be reached effectively under the proposed control mechanism. Furthermore, it is shown that the Zeno behavior can be excluded from the designed triggering mechanism. Finally, simulations on a multiagent system consisting of interconnected unmanned intelligent vehicles are conducted to verify the results.

Fully Distributed Event-Driven Coordination With Actuator Faults.

This article investigates the event-driven fault-tolerance (ETFT) consensus problem for general linear multiagent systems (MASs) with partial loss of effectiveness (PLOE) and bias faults of actuators in leader-follower networks. Each agent's controller is only updated relatively infrequently at its event moments. A desirable feature of this article is that the proposed event-driven algorithm is fully distributed also independent of global information and additive fault boundaries. Based on this, a consensus error prediction model is used to avoid the limitation that each agent needs to monitor its neighbors' state under event-driven conditions continuously. We further excluded the Zeno behavior by proving that any adjacent event interval for each agent is greater than zero. The simulations verify our results.

Adaptive Event-Triggered Average Tracking Control With Activable Event-Triggering Mechanisms

The fully distributed adaptive event-triggered average tracking protocol for general linear multiagent systems (MASs) with a positive minimum interevent time (PMIET) is established in an asynchronous way. First, a fully distributed event-triggered detector and controller for each agent that includes internal variables and adaptive gains are designed to track the average of multiple time-varying references signals asymptotically via intermittent communication without the requirement of global information. Then, activable dynamic event-triggering mechanisms are designed for the detector and the controller, respectively, which can only be activated after certain specific instants; that is, the triggering condition needs to be monitored only after the event-triggering mechanism has been activated. The time interval between the event-triggered instant and a specific activation instant ensures that the event-triggering mechanisms for the detectors and the agents have PMIETs. Finally, the application of spacecraft formation tracking in low Earth orbit illustrates the availability of the theoretical results.

Dynamic Event-Triggered Consensus for Linear Multi-Agent Systems With Hybrid Intelligence

In this brief, consensus control is investigated for general linear multi-agent systems (MASs) over undirected communication topologies. Considering that the agents in MASs may have nonidentical intelligence characteristics, the concept of intelligent level is introduced to characterize the intelligence characteristics of agents. A novel dynamic event-triggered communication mechanism is developed based on periodic sampled data and the intelligent levels of agents, in which the threshold parameter of the event-triggered condition updates periodically in accordance with a prescribed dynamic law. By making use of a delayed system method and Lyapunov stability theory, some sufficient conditions are derived to guarantee the desired consensus under a novel delicately designed control protocol. Finally, the effectiveness of the proposed approach is validated by a simulation example.

Topology-based dynamic event-triggered leader-following consensus of multi-agent systems under switching topologies

This paper is devoted to the topology-based dynamic event-triggered leader-following consensus issue of general linear multi-agent systems under switching topological structures. The novel topology-based distributed dynamic event-triggered rule is formed, in which a topology-based dynamic auxiliary variable is introduced to reduce the conservatism and save resources. Under novel triggering rules, topology-based distributed event-triggered controllers are constructed. Different control gains are designed for different topological structures. Compared with existing works, conservatism is further reduced. Then the leader-following consensus is achieved with a global exponential convergence rate. Moreover, the average dwell time method is adopted to relax restrictions on the switching speed of topological structures and an original analytical thought is put forward to rule out the Zeno phenomenon concisely and clearly. Finally, two numerical examples and a realistic mass–spring system are utilized to verify the feasibility and superiority of the proposed theory.

Distributed Adaptive Event-Triggered TVGF for Generic Linear Multi-Agent Systems Under Directed Graph

This paper investigates event-triggered time-varying grouping formation (TVGF) problem for generic linear homogeneous multi-agent systems under directed graphs. A distributed adaptive event-triggered TVGF algorithm is proposed to ensure that the goal of TVGF can be achieved and the communication frequency between agents is reduced. Compared with previous formation control methods, the algorithm presented in this paper can complete the group formation task while saving communication energy. In addition, the algorithm’s dependence on global network information is also eliminated by using adaptive techniques. Finally, the availability of the proposed control law is established by numerical simulation.

Distributed Semi-Global Output Feedback Formation Maneuver Control of High-Order Multiagent Systems

This article addresses the formation maneuver control problem of leader–follower multiagent systems with high-order integrator dynamics. A distributed output feedback formation maneuver controller is proposed to achieve desired maneuvers so that the scale, orientation, translation, and shape of formation can be manipulated continuously, where the followers do not need to know or estimate the time-varying maneuver parameters only known to the leaders. Compared with existing relative-measurement-based formation maneuver control, the advantages of the proposed method are that it is output (relative output) feedback based and shows how to realize different types of formation shape. In addition, it can be applied to nongeneric and nonconvex nominal configurations and the leaders are allowed to be maneuvered. It is worth noting that the proposed method can also be extended to general linear multiagent systems under some additional conditions. The theoretical results are demonstrated by a simulation example.