A Lyapunov redesign of coordination algorithms for cyberphysical systems

Abstract: The objective is to design distributed coordination strategies for a network of agents in a cyber-physical environment. In particular, we concentrate on the rendez-vous of agents having double-integrator dynamics with the addition of a damping term in the velocity dynamics. We start with distributed controllers that solve the problem in continuous-time, and we then explain how to implement these using event-based sampling. The idea is to define a triggering rule per edge using a clock variable which only depends on the local variables. The triggering laws are designed to compensate for the perturbative term introduced by the sampling, a technique that reminds of Lyapunov-based control redesign. We first present an event-triggered solution which requires continuous measurement of the relative position and we then explain how to convert it to a self-triggered policy. The latter only requires the measurements of the relative position and velocity at the last transmission instants, which is useful to reduce both the communication and the computation costs. The strategies guarantee the existence of a uniform minimum amount of times between any two edge events. The analysis is carried out using an invariance principle for hybrid systems.