Development of a Basic Formation Control System for Heterogeneous Autonomous Marine Vehicles and Its Sea Trials in Suruga Bay

The National Maritime Research Institute of Japan has been conducting research on developing seafloor survey technology using multiple autonomous underwater vehicles (AUVs) and a single autonomous surface vehicle (ASV), mainly from the perspective of efficient operation. To operate several AUVs simultaneously, sometimes, a group of AUVs of different manufacturers and design concepts should be regulated. We proposed in this study a basic formation control system that enables the control of multiple AUVs by minimizing the modifications for standardization among an ASV and AUVs and tested the proposed system under actual sea conditions. Common acoustic devices and communication protocols were installed to enable all vehicles to communicate and be positioned. A two-step operation of initial position error correction and speed control allows the ASV to maintain communication and positioning with each AUV to accomplish a seafloor survey mission. Sea trials were conducted for 4 days in June 2022 in Suruga Bay, Japan, at a depth of 120 m, using four AUVs and one ASV from different manufacturers. The basic formation control system kept all AUVs within communication range, and then, data from all AUVs were combined to successfully acquire bathymetric data. Despite the problem of sonar interference, satisfactory results were obtained, and the capability of the basic formation control of heterogeneous cruising AUVs was confirmed.