A multi-layer control scheme for multi-robot formations with obstacle avoidance

This paper presents a multi-layer scheme to control a formation of n mobile robots, including a strategy for obstacle avoidance. The controller adopted is able to guide the robots to compose the desired formation and to track a desired trajectory, avoiding obstacles during the navigation. Two planning layers are responsible for organizing the navigation of the individual robots towards the desired formation, minimizing energy consumption, and for changing the robots reference signals in order to avoid collisions. Stability analysis performed for the closed-loop system shows that the formation errors are ultimately bounded. Finally, simulation results for a group of four unicycle-like mobile robots are presented, which show that the proposed scheme is capable of avoiding collisions and of redefining robots' pose in order to improve system performance.