  Multi-agent systems cooperation to achieve global goals is usually limited by
sensing, actuation, and communication issues. At the local level, continuous
measurement and actuation is only approximated by the use of digital mechanisms
that measure and process information in order to compute and update new control
input values at discrete time instants. Interaction with other agents or
subsystems takes place, in general, through a digital communication channel
with limited bandwidth where transmission of continuous-time signals is not
possible. Additionally, communication channels may be subject to other
imperfections such as time-varying delays. This paper considers the problem of
consensus (or synchronization of state trajectories) of multi-agent systems
that are described by general linear dynamics and are connected using
undirected graphs. An event-triggered consensus protocol is proposed, where
each agent implements discretized and decoupled models of the states of its
neighbors. This approach not only avoids the need for continuous communication
between agents but also provides a decentralized method for transmission of
information in the presence of time-varying communication delays where each
agent decides its own broadcasting time instants based only on local
information. This method gives more flexibility for scheduling information
broadcasting compared to periodic and sampled-data implementations. The use of
discretized models by each agent allows for a periodic event-triggered strategy
where continuous actuation and continuous measurement of the states are not
necessary.
