Formation Control of a Drifting Group of Marine Robotic Vehicles

This paper presents a comparative study into three strategies for planar (2D) formation control of autonomous underwater/surface vehicles (AUVs/ASVs) in the presence of ocean or river currents. Deploying multiple AUVs in formation would provide large-scale spatial and temporal data for oceanographic research. However, multi-AUV formation control is difficult because of the communication and navigation constraints of the underwater environment. The strategies we developed to address these challenges are distributed, use relative positions of neighboring vehicles to coordinate, and leverage current to increase endurance. We present simulation results for a group of 20 AUVs operating in 4D ocean currents, and compare control strategies in terms of energy expenditure and formation quality. We validated the most promising strategy with real robot experiments using three ASVs on the Charles River, and provide an initial analysis of the data.