Event-Triggered Consensus of Uncertain Euler-Lagrange Multi-Agent Systems on Jointly Connected Digraphs

Authors: ximing  yang
Venue: IEEE_org_ICIST_2024_Conference
Published: 2024-08-21 07:26:59

Abstract: This paper presents a fully distributed event-triggered protocol aimed at solving the consensus problem in uncertain Euler-Lagrange (EL) multi-agent systems (MASs) under jointly connected digraphs. Firstly, distributed event-driven reference generators are introduced to generate continuously differentiable reference signals via event-based communication within the jointly connected digraphs. Unlike some existing work, this approach only necessitates the transmission of agent states, without the need for virtual internal reference variables, among agents. Secondly, adaptive controllers are implemented, allowing each agent to track the reference signals. The uncertain parameters are shown to converge to their actual values under the initially exciting (IE) condition. It is established that the uncertain EL MAS achieves asymptotic state consensus using the proposed event-triggered protocol, which includes the reference generators and adaptive controllers. A distinguishing feature of the proposed protocol is its fully distributed characteristic, as it does not require global information about the jointly connected digraphs. Moreover, a minimum inter-event time (MIET) is guaranteed. Lastly, two simulations are carried out to confirm the effectiveness of the proposed protocol.

Main paper: 
 i. introduction: 
 Over the last two decades, the distributed cooperative control problem of multi-agent systems (MASs) has emerged as a central research area in the control community, driven by its broad range of applications [1], [2] . Key topics include consensus, flocking, and formation Communication among agents is generally necessary for reaching consensus in the cooperative control of MASs, as is well known [11] . Nevertheless, continuous communication can be inefficient or even impractical due to the limited communication bandwidth and energy available to each agent. To address this, distributed event-triggered protocols have been developed, which facilitate communication between neighboring agents only when a specific event-triggering condition is met [12] . A key challenge in event-triggered protocols is avoiding Zeno behavior, where an infinite number of events occur within a finite time period. Two commonly adopted strategies to prevent Zeno behavior involve the use of a contradiction argument [13] [32], and [33] . Specifically, the consensus problem for Euler-Lagrange (EL) MASs under fixed topologies is solved through distributed control protocols using continuous communication in [7] and [31] , and this work has been extended to jointly connected topologies in [30] and [32] . More recently, eventtriggered communication mechanisms have been employed for the cooperative control of EL MASs [34], [35] . In [33] , a quantized sampled-data control method is developed to achieve robust consensus for a class of nonlinear MASs, but the topologies are constrained to be fixed in [33] and [34] . The event-triggered protocols proposed in [34] and [35] require global information about the communication topologies, and no positive MIET is provided. 
 
 Appendix: