  One aspect of the ever-growing need for long term autonomy of multi-robot
systems, is ensuring energy sufficiency. In particular, in scenarios where
charging facilities are limited, battery-powered robots need to coordinate to
share access. In this work we extend previous results by considering robots
that carry out a generic mission while sharing a single charging station, while
being affected by air drag and wind fields. Our mission-agnostic framework
based on control barrier functions (CBFs) ensures energy sufficiency (i.e.,
maintaining all robots above a certain voltage threshold) and proper
coordination (i.e., ensuring mutually exclusive use of the available charging
station). Moreover, we investigate the feasibility requirements of the system
in relation to individual robots' properties, as well as air drag and wind
effects. We show simulation results that demonstrate the effectiveness of the
proposed framework.
