Using a swarm of robots to get tasks done without colliding is not always straightforward. Georgia Tech roboticist Magnus Egerstedt has come up with a safety approach that allows a team of robots to move within inches of each other without colliding.
the bots are using a set of safe states and barrier certificates to ensure each stays in its own safe set throughout the entire maneuver.
The system allows robots to complete their tasks with minimal changes to avoid collisions. Georgia Tech has more on this approach here.