Directed Switching Topologies Research Articles

Distributed Leader-Following Consensus of Feedforward Nonlinear Delayed Multiagent Systems via General Switched Compensation Control.

This work examines the distributed leader-following consensus problem of feedforward nonlinear delayed multiagent systems involving directed switching topologies. In contrast to the existing studies, we focus on time delays acting on the outputs of feedforward nonlinear systems, and we permit that the partial topology dissatisfy the directed spanning tree condition. In the cases, we present a novel output feedback-based general switched cascade compensation control method that addresses the above-mentioned problem. First, we put forward a distributed switched cascade compensator by introducing multiple equations, and we design the delay-dependent distributed output feedback controller with the compensator. Subsequently, when the control parameters-dependent linear matrix inequality is met and the switching signal of the topologies obeys a general switching law, we prove that the established controller can render that the follower's state asymptotically tracks the leader's state by employing an appropriate Lyapunov-Krasovskii functional. The given algorithm allows output delays to be arbitrarily large and increases the switching frequency of the topologies. A numerical simulation is presented to demonstrate the practicability of our proposed strategy.

Collaborative communication-based ocean observation research with heterogeneous unmanned surface vessels

Unmanned surface vehicles (USVs) are crucial in ensuring maritime safety and observation, attracting widespread attention and research. However, a single USV exhibits limited performance and cannot effectively observe complex marine environments. In contrast, clusters of USVs can collaborate to execute complex maritime tasks, thereby enhancing the overall operational efficiency. USVs typically form heterogeneous clusters by combining vehicles with varying maneuverabilities and communication network capabilities. This has sparked an increased interest in cooperative communication research within heterogeneous USV clusters. The heterogeneous USVs discussed in this paper share the same dynamic model; however, they differ in dynamic parameters and communication capabilities. First, this study establishes a three-degree-of-freedom motion mathematical model for an underdriven USV considering environmental interference. It estimates the dynamic parameters of four USVs and evaluates their communication abilities, laying the foundation for researching the cooperative control of heterogeneous USV clusters and their application in Ocean Observation. Next, the communication capability of the USVs is assessed by studying the communication mode and signal transmission loss within the USV clusters. This study investigates the problem of cooperative communication in USV cluster formation, starting with the communication delay of USV clusters under a directed switching topology. Finally, a coherent formation controller is designed under a switching communication topology to address the dynamic transformation of communication topologies within heterogeneous USV clusters. This verifies that heterogeneous USV clusters can seamlessly form and maintain formation shapes during communication topology transformations through formation simulation experiments involving four heterogeneous USVs was 22% higher than that of dispersed control topology structures. This study provides a solid foundation for future investigations into the cooperative control of heterogeneous USV clusters and their applications in marine observations.

Structural controllability of multi‐agent systems with directed switching topologies

AbstractThis paper considers structural controllability of multi‐agent systems (MASs) with switching topologies, in which each interaction topology is modeled by a weighted digraph. Under the adopted relative protocol, the MASs with directed switching topologies are modeled by a switched system with parameter interdependence. The technique of linear parameterization, the graph theory, and so forth are applied to tackle the structural controllability of the switched system. A graph‐theoretic interpretation for structural controllability of the system is proposed. Examples with single leader and multiple leaders are presented to illustrate our work.

Dynamic Event-Triggered Consensus of Nonlinear Lur’e Networks With Directed Switching Topologies

Dynamic Event-Triggered Consensus of Nonlinear Lur’e Networks With Directed Switching Topologies

Semi-global asymptotic state agreement of nonlinear multi-agent systems with communication delays under directed switching topologies

This paper investigates the semi-global state agreement problem for continuous-time nonlinear multi-agent systems with communication delays under direct and switching topologies. A systematic solution to the semi-global state agreement is presented and based on which a sufficient and necessary condition on the control laws is obtained, as long as the direct and switching communication topologies satisfy a mild joint connectivity assumption. Illustrative simulations are provided to validate the efficacy of the proposed theoretical results.

Asymptotical Neuro-Adaptive Consensus of Multi-Agent Systems With a High Dimensional Leader and Directed Switching Topology.

We study the asymptotical consensus problem for multi-agent systems (MASs) consisting of a high-dimensional leader and multiple followers with unknown nonlinear dynamics under directed switching topology by using a neural network (NN) adaptive control approach. First, we design an observer for each follower to reconstruct the states of the leader. Second, by using the idea of discontinuous control, we design a discontinuous consensus controller together with an NN adaptive law. Finally, by using the average dwell time (ADT) method and the Barbǎlat's lemma, we show that asymptotical neuroadaptive consensus can be achieved in the considered MAS if the ADT is larger than a positive threshold. Moreover, we study the asymptotical neuroadaptive consensus problem for MASs with intermittent topology. Finally, we perform two simulation examples to validate the obtained theoretical results. In contrast to the existing works, the asymptotical neuroadaptive consensus problem for MASs is firstly solved under directed switching topology.

Event-based [formula omitted] consensus tracking for multi-agent systems under switching networks

This paper systematically investigates consensus tracking of linear multi-agent systems with disturbances over directed switching topologies. Both state and output feedback H∞ controllers are jointly synthesized with the triggering mechanism. First, a state-based event-triggered H∞ controller design for achieving consensus tracking is carried out, which can result in settling the occurrence of disturbances and the reduction of controller updates as well as averting Zeno behavior. Considering the case that only output information of agent is required, an event-triggered H∞ output feedback controller is then proposed and sufficient condition for the solvability of consensus tracking problem are also derived. Compared with the existing results, the effects of disturbances on directed switching topologies can be tackled when continuous communication and full-state information of the agent are not needed. Numerical simulation are finally conducted to illustrate the effectiveness of the proposed methods.

Asymptotical Consensus of MIMO Linear Multiagent Systems With a Nonautonomous Leader and Directed Switching Topology: A Continuous Approach

In this paper, we investigate the asymptotical consensus tracking problems for multiple-input-multiple-output (MIMO) linear multi-agent systems (MASs) with directed switching topology and a non-autonomous leader subject to nonzero unknown inputs. First, we design a full order unknown input observer (UIO) based on relative outputs to estimate the relative full states. Based on this UIO, we design a continuous consensus controller by introducing a decay function which remains positive into the term that is used to eliminate the effects of leader's nonzero inputs. And by using the multiple Lyapunov functions (MLFs) method, we prove that asymptotical consensus can be achieved if the average dwell time (ADT) is greater than a positive threshold. Second, we design a continuous consensus controller based on a reduced order UIO that can significantly simplify calculations. Finally, we give two examples about multiple unmanned aerial vehicles (UAVs) to verify the theoretical results. Compared with existing works, the continuous controllers here can not only achieve zero error consensus tracking, but also are chattering free.

Event-triggered consensus control based on maximum correntropy criterion for discrete-time multi-agent systems

An event-triggered consensus problem of discrete-time multi-agent systems with impulsive noise under directed switching topology is investigated in this paper, where the control input of each agent is determined by its own state information and the state information of its neighbors that may be corrupted by impulsive noise. Firstly, to reduce the adverse effect of impulsive noise on consensus performance of the discrete-time multi-agent systems, maximum correntropy criterion (MCC) derived from information theoretic learning is introduced to calculate the communication weights among the agents, and an event-triggered strategy is adopted to drive the state variables of each agent to eventually converge to a same value. Secondly, the condition to guarantee consensus of the discrete-time multi-agent systems is derived by graph theory and Lyapunov stability theorem. Finally, the effectiveness of the theory is verified by several numerical simulations.

Robust formation control of unmanned aerial vehicle swarms subject to jointly connected directed switching topologies

针对联合连通有向切换拓扑网络条件下存在外界扰动的无人机集群鲁棒时变编队与轨迹跟踪控制问题进行了研究. 首先, 依据无人机真实飞行状态信息、期望队形信息与需要跟踪的轨迹信息误差, 以及联合连通通信拓扑网络条件下能够相互通信无人机期望飞行状态与实际飞行状态之间误差信息设计出了无人机集群系统的编队控制方法. 然后通过一类特殊的矩阵分解将集群系统时变编队与轨迹跟踪控制问题转换成联合连通快速时间平均系统的渐近稳定控制问题, 进一步提出了系统渐近稳定的充分条件, 并通过建立的分段连续Lyapunov泛函进行了证明. 最后仿真结果验证了本文所提方法能够实现联合连通有向切换拓扑网络条件下无人机集群的时变编队与轨迹跟踪控制飞行.

A chattering free consensus controller for multiple Lur’e systems with a non-autonomous leader and directed switching topology

A chattering free consensus controller for multiple Lur’e systems with a non-autonomous leader and directed switching topology

Distributed asynchronous consensus control of nonlinear multi-agent systems under directed switching topologies

This paper proposes a new Lyapunov function to study the distributed consensus problem for nonlinear multi-agent systems whose topologies are asynchronously switched with respect to observers. To be specific, we take into account the detection delay of topology switchings when designing the corresponding observers. The novelty of the design arises in the continuity of the Lyapunov function at the switching instants and in the discontinuity when the topology modes and the observer modes are matched. This property can possibly allow the value of the Lyapunov function to be non-increasing during the unmatched intervals, which reduces the conservativeness of topology switching signal in the sense that a more relaxed condition than state-of-the-art ones can be obtained. Moreover, a new Laplacian matrix is incorporated into our design to handle the dilemma that each agent can only receive the local neighboring information from the common neighbors before and after topology switchings. Hypersonic flight vehicles have been employed to verify the effectiveness of the theoretical findings.

Event-triggered tracking control of stochastic switched multi-agent systems subjected to input saturation

This paper focuses on the tracking control problem of stochastic nonlinear multi-agent systems subjected to input saturation and directed switching topologies. In addition, the external disturbances are also considered to ensure the system robustness. A dynamic event-triggered consensus scheme based on a switching compensator for every follower agent is proposed via output feedback. By the Lyapunov stability analysis, a sufficient condition for switching signal is obtained such that the tracking errors can reach a small compact set of the origin. Moreover, the proposed event-triggered strategy by fully exploiting the dynamic gain can save resources effectively and avoid the Zeno behavior. Finally, simulation studies confirm the effectiveness of the theoretical results.

Consensus Disturbance Rejection of MIMO Linear Multiagent Systems With Directed Switching Topologies: A Reduced Order Observer Approach

In this brief, consensus disturbance rejection problem is investigated for multiple-input-multiple-output (MIMO) linear multi-agent systems (MASs) subject to non-vanishing disturbances under directed switching topologies. First, we design a reduced order unknown input observer (UIO) based only on the relative outputs to estimate the relative full states. Then a consensus controller together with a disturbance observer (DO) is designed to achieve the cooperative goal. Second, by using the average dwell time (ADT) method, it is proven that consensus can be achieved if the ADT is greater than a positive threshold, meanwhile the non-vanishing disturbances are attenuated by DO. Finally, theoretical result is verified by performing simulation.

Consensus Problem and Formation Control for Heterogeneous Multi-Agent Systems with Switching Topologies

The cooperative control problem of discrete-time multi-agent systems (MASs) is discussed, and bounded uncertain time-delays and directed switching topologies are considered. By applying model transformations and matrix theory, an augmented system method is introduced to handle a heterogeneous time-delay MAS. Then, the consensus problem of the system is turned to the convergence issue of the product of innumerable row stochastic matrices. Sufficient conditions for asymptotic consensus of the system under directed switching topologies are obtained. Moreover, a novel consensus-based formation control strategy is designed to gain sufficient and necessary conditions for the formation control of a second-order differential robot system. Finally, the effectiveness of the obtained results is verified through simulations.

Completely Event-Triggered Consensus for Multiagent Systems With Directed Switching Topologies.

This article studies the leader-following consensus of multiagent systems (MASs) with completely event-triggered mechanisms (CETMs) and directed switching topologies. When most event-triggered schemes in MASs only reduce each agent's data transmissions to neighbor agents, CETMs further reduce data transmissions to actuators with one triggered function in each agent. To guarantee the switching links utilized by CETMs contain a directed spanning tree at any time, triggered decisions are improved to include the instants at which each agent's output links or leader link change. Furthermore, a less conservative method based on matrix inequalities is combined to minimize the allowable average dwell time (ADT) of switching topologies under the design conditions of CETMs. Based on multiple Lyapunov functions (MLFs), the sufficient conditions for controller gains that guarantee the leader-following consensus of MASs are proposed when the ADT of switching topologies is larger than the allowable value. Finally, an example of autonomous underwater vehicles (AUVs) is given to illustrate the effectiveness of CETMs.

Fully distributed containment of multiple‐input‐multiple‐output linear multi‐agent systems with multiple nonautonomous leaders

SummaryIn this article, we study the fully distributed containment problem for multiple‐input‐multiple‐output linear multi‐agent systems (MASs) with multiple nonautonomous leaders (i.e., leaders with nonzero inputs). First, based on an unknown input observer (UIO) with full order and by using unit vector method, we design an adaptive discontinuous controller, where the adaptive law is used to adjust network coupling strengths. And by using Barbǎlat lemma, we show that fully distributed containment can be achieved if the graph is connected and the subgraph among multiple followers is detail balanced. Second, we study fully distributed containment for MASs under an adaptive discontinuous controller based on a UIO with reduced order. Moreover, we study the case with directed switching topology. Finally, we perform simulations on a team of aircrafts to validate the theoretical results.

Containment problem for multi‐agent systems with position and velocity constraints

AbstractThe containment problem is investigated for networked second‐order agents with nonuniform position and nonconvex velocity constraints under directed switching topologies. A distributed containment algorithm is designed for each agent to drive it into the convex target area formed by multiple leaders. The proposed control strategy only utilizes the information of each agent and its neighbor interaction. Theoretical analysis demonstrates that the constrained containment problem can be addressed only if each agent has a directed communication path from at least one leader to it in the union of the graphs. Finally, several numerical simulation results are presented to demonstrate the proposed control schemes.

Consensus of Lur’e Multi-Agent Systems With Directed Switching Topology

We study the consensus tracking problems of Lur’e multi-agent systems (MASs) with directed switching topology and a leader that is subject to unknown inputs. We firstly use the pure relative outputs to design a distributed unknown input observer (UIO) that can track the relative states exactly. Then we use this UIO to design a discontinuous controller which contains a consensus part and a discontinuous part, where the impacts of the leader’s unknown inputs can be completely removed by the discontinuous part. Furthermore, by using the average dwell time (ADT) method, we show that asymptotical consensus can be achieved if the ADT is larger than a positive threshold. Secondly, we design a continuous controller under which the consensus tracking error is uniformly ultimately bounded (UUB). Finally, we perform a simulation on the multiple Chua’s circuits to validate the theoretical result.

A new approach using multiple Lyapunov functions for bipartite consensus of multi-agents over directed switching signed graphs

This paper investigates a new approach for the bipartite (cooperative–competitive) consensus control design for a class of nonlinear agents with Lipschitz dynamics under directed switching topologies. The design technique utilizes multiple Lyapunov functions (MLFs), inequality-based criteria, and average dwell-time (ADT) for switching instances to develop relaxed and less conservative constraints. The results are derived for structurally balanced signed graphs which switch among different configurations with persistent or frequent directed spanning tree (DST), rooted at the leader node. Further, results are also investigated for the dynamic leader agent with non-zero norm-bounded control input. To the best of our knowledge, bipartite consensus of a generic form of Lipschitz nonlinear agents under directed switching topologies has been addressed for the first time. In addition, advanced concepts of MLFs and ADT are used for dealing with switching among signed communication topologies. Numerical simulations to validate the proposed theoretical analysis are provided for different conditions.