Jointly-connected Topologies Research Articles

Time-Varying Formation Control With Transient Performance for Multiagent Systems Under Jointly Connected Topologies

Time-Varying Formation Control With Transient Performance for Multiagent Systems Under Jointly Connected Topologies

Tracking-Oriented Formation Control for Unmanned Aerial Vehicle Swarm Through Output Feedback Under Jointly-Connected Topologies

Tracking-Oriented Formation Control for Unmanned Aerial Vehicle Swarm Through Output Feedback Under Jointly-Connected Topologies

Sliding-Mode-Based Admissible Consensus Tracking of Nonlinear Singular Multiagent Systems Under Jointly Connected Topologies.

The admissible consensus tracking problem of nonlinear singular multiagent systems (SMASs) with time-varying delay, uncertainties, and external disturbances under jointly connected topologies is investigated in this article. First, the sliding-mode control (SMC) is applied to effectively reduce the adverse effects of uncertainties and nonlinearities of systems. Then, by the combination of admissible analysis, the Cauchy convergence criterion, and SMC, the sufficient conditions for the admissible consensus tracking and disturbance rejection of SMASs under jointly connected topologies are provided. Furthermore, a distributed SMC law is designed such that the sliding-mode dynamics trajectories reach the sliding surface in finite time. Finally, the simulation results are utilized to indicate the effectiveness of the presented methods.

Event-Triggered Cooperative Output Regulation of Linear Multi-Agent Systems Under Jointly Connected Topologies

This paper addresses the cooperative output regulation problem of linear multi-agent systems under switching communication topologies. A distributed event-triggered control scheme is proposed so that the cooperative output regulation problem is solved with only intermittent communication. The communication topology is not required to be connected at every time instant under the jointly connected assumption. With the proposed triggering mechanism, each agent only transmits the information to its neighbors at its own triggering times or the switching times. By introducing a fixed timer, Zeno behavior is strictly excluded for each agent. The effectiveness of the proposed control scheme is demonstrated by an example.

Consensus for Mixed‐Order Multiagent Systems over Jointly Connected Topologies via Impulse Control

Because of the complexity of the environment, the dynamics of agents in the same system may be different. That is, the dynamics of some agents may be first ordered, and the others may be second ordered, even high ordered. In addition, the network topologies of systems are always varying over time. Because of these facts, this paper studies the consensus problem of the mixed‐order multiagent networks over the jointly connected topologies. By adopting the impulse control technique, some control protocols are proposed based on the information of the agents themselves and their neighbors. Several simulation results are given to verify the correctness of the theoretical results.

Time-Varying Formation Control For Second-Order Discrete-Time Multi- Agent Systems With Switching Topologies and Nonuniform Communication Delays

Time-varying formation control and velocity tracking problems for second-order discrete-time multi-agent systems with switching jointly-connected topologies and nonuniform communication delays are investigated. A local information-based distributed protocol is designed by utilizing the instantaneous states of the agent itself and the delayed states of its neighbors. Through model transformation and stability analysis, an explicit mathematical description of a feasible time-varying formation set is proposed. Necessary and sufficient conditions for the systems with switching topologies and nonuniform communication delays to achieve the feasible time-varying formation are obtained. The coupling constraints on the gain parameters and sampling period are proposed, so as to guide the design of parameters in the protocol. We include the effects of velocity tracking error damping gain in the protocol and derive milder conditions which allow for not only bounded nonuniform communication delays but also for dynamically switching directed graphs that are jointly connected. The numerical examples are further presented to illustrate the validity and effectiveness of the obtained results.

Containment control of leader-following multi-agent systems with jointly-connected topologies and time-varying delays

This paper considers the containment control problem for leader-following multi-agent systems in the presence of dynamically switching topologies with communication delays. Two types of control algorithms are proposed for containment control with first-order dynamics and second-order dynamics. By applying modern control theory and algebraic graph theory, the stabilities of two containment control algorithms are analyzed on Lyapunov–Krasovskii method. Moreover, some sufficient conditions are provided through further researching the connected portion of multi-agent systems, which can ensure that the containment control can be achieved asymptotically when communication topologies are jointly-connected. Finally, some simulation examples are provided to demonstrate the effectiveness of two proposed algorithms.

Sampled Measurement Output Feedback Control of Multi-Agent Systems With Jointly-Connected Topologies

This note studies the consensus problem of a class of multi-agent systems (MASs) with linear dynamics, where each agent is able to use the specified measurement output (e.g., position) relative to its neighbors at certain sampling instants. It is assumed that the network has switching but jointly-connected topologies in the sense that the union of the associated graphs over a certain time interval always has a spanning tree. Under this assumption, a linear sampled measurement output feedback controller is proposed to achieve full state consensus for a sufficiently small sampling period.

Formation Flight Control of Multi-UAV System with Communication Constraints

Three dimensional formation control problem of multi-UAV system with communication constraints of non-uniform time delays and jointly-connected topologies is investigated. No explicit leader exists in the formation team, and, therefore, a consensus-based distributed formation control protocol which requires only the local neighbor-toneighbor information between the UAVs is proposed for the system. The stability analysis of the proposed formation control protocol is also performed. The research suggests that, when the time delay, communication topology, and control protocol satisfy the stability condition, the formation control protocol will guide the multi-UAV system to asymptotically converge to the desired velocity and shape the expected formation team, respectively. Numerical simulations verify the effectiveness of the formation control system.

Adaptive Tracking Control of Second-Order Multiagent Systems with Jointly Connected Topologies

This paper considers a consensus problem of leader-following multiagent system with unknown dynamics and jointly connected topologies. The multiagent system includes a self-active leader with an unknown acceleration and a group of autonomous followers with unknown time-varying disturbances; the network topology associated with the multiagent system is time varying and not strongly connected during each time interval. By using linearly parameterized models to describe the unknown dynamics of the leader and all followers, we propose a decentralized adaptive tracking control protocol by using only the relative position measurements and analyze the stability of the tracking error and convergence of the adaptive parameter estimators with the help of Lyapunov theory. Finally, some simulation results are presented to demonstrate the proposed adaptive tracking control.

Distributed formation flight control of multi-UAV system with nonuniform time-delays and jointly connected topologies

This paper aims to investigate formation control problem of multi-UAV system with nonuniform time-delays and jointly-connected topologies. No explicit leader exists in the formation team, and therefore a consensus-based distributed formation control protocol which requires only the local neighbor-to-neighbor information between UAVs is proposed for the system. The stability analysis of the proposed formation control protocol is also performed. The research suggests that when the time-delay, communication topology and control protocol satisfy the stability condition, the formation control protocol will guide the multi-UAV system asymptotically converge to the desired velocity and shape the expected formation team, respectively. Numerical simulations verify the effectiveness of the formation control system.

Distributed adaptive consensus for multiple mechanical systems with switching topologies and time-varying delay

This paper studies the adaptive consensus problem of networked mechanical systems with time-varying delay and jointly-connected topologies. Two different consensus protocols are proposed. First, we present an adaptive consensus protocol for the connected switching topologies. Based on graph theory, Lyapunov stability theory and switching control theory, the stability of the proposed algorithm is demonstrated. Then we investigate the problem under the more general jointly-connected topologies, and with concurrent time-varying communication delay. The proposed consensus protocol consists of two parts: one is for the connected agents which contains the current states disagreement among them and the other is designed for the isolated agents which contains the states difference between the current and past. A distinctive feature of this work is to address the consensus control problem of mechanical systems with unknown parameters, time-varying delay and switching topologies in a unified theoretical framework. Numerical simulation is provided to demonstrate the effectiveness of the obtained results.

Second-Order Consensus of Leader-Following Multi-Agent Systems with Jointly Connected Topologies and Time-Varying Delays

In this paper, we discuss, respectively, second-order leader-following consensus problems with and without time-varying communication delays. Lyapunov theorems and matrix approach are employed to prove that all the leader-following agents will achieve second-order consensus if the velocity communication topology between the leader and each following agent is connected and the position communication topologies of all the leader-following agents are jointly connected. Several simulation results are presented to support the effectiveness of our theoretical results.

A new approach to average consensus problems with multiple time-delays and jointly-connected topologies

This paper investigates average consensus problem in networks of continuous-time agents with delayed information and jointly-connected topologies. A lemma is derived by extending the Barbalat's Lemma to piecewise continuous functions, which provides a new analysis approach for switched systems. Then based on this lemma, a sufficient condition in terms of linear matrix inequalities (LMIs) is given for average consensus of the system by employing a Lyapunov approach, where the communication structures vary over time and the corresponding graphs may not be connected. Finally, simulation results are provided to demonstrate the effectiveness of our theoretical results.

Multi-agent consensus with diverse time-delays and jointly-connected topologies

This paper investigates consensus problems in networks of continuous-time agents with diverse time-delays and jointly-connected topologies. For convergence analysis of the networks, a class of Lyapunov–Krasovskii functions is constructed which contains two parts: one describes the current disagreement dynamics and the other describes the integral impact of the dynamics of the whole network over the past. By a contradiction approach, sufficient conditions are derived under which all agents reach consensus, even though the communication structures between agents dynamically change over time and the corresponding graphs may not be connected. The obtained conditions are composed of a sum of decoupled parts corresponding to each possible connected component of the communication topology. Finally, numerical examples are included to illustrate the obtained results.

Consensus of a Class of Second-Order Multi-Agent Systems With Time-Delay and Jointly-Connected Topologies

This technical note investigates consensus problems of a class of second-order continuous-time multi-agent systems with time-delay and jointly-connected topologies. We first introduce a neighbor-based linear protocol with time-delay. Then we derive a sufficient condition in terms of linear matrix inequalities (LMIs) for average consensus of the system. Furthermore, we discuss the case where the time-delay affects only the information that is being transmitted and show that consensus can be reached with arbitrary bounded time-delay. Finally, simulation results are provided to demonstrate the effectiveness of our theoretical results.