Development of Cooperative Formation Control System for Multiple Cruising AUVs With Acoustic Positioning Between AUVs

The National Maritime Research Institute (NMRI), in collaboration with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the lead agency of the Cabinet Office Strategic Innovation Creation Program (SIP) 3rd Term, has been promoting the development of a cooperative formation control system using cruising AUVs and equipment with acoustic positioning device on the seafloor, called an acoustic lighthouse. Safety management, such as AUV status confirmation and loss prevention, is paramount when multiple AUVs are deployed simultaneously in actual sea areas. This study proposes a cooperative formation control system based on short-range acoustic positioning between an acoustic lighthouse and an AUV or multiple AUVs. In the proposed system, absolute position correction is performed by acoustic positioning between an AUV and an acoustic lighthouse on the seafloor. Second, multiple cruising AUVs are divided into the roles of a reference AUV and follower AUVs, and the method called “Reference-follower control” is performed to maintain the desired positioning relationship from the reference AUV through periodic acoustic positioning from the follower AUV to the reference AUV. This paper verifies the effectiveness of the proposed “Reference-follower control” by simulating three AUVs. Next, we implemented the proposed method on two navigational AUVs owned by NMRI and conducted a field test in a 100 m deep-sea area in Suruga Bay, Japan. The two AUVs succeeded in stable AUV-AUV positioning and completed seafloor observations while adjusting to the desired relative positions. As a result, highly accurate seafloor topographic data with a mesh width of 1 m was obtained, proving the usefulness of the proposed method in actual sea areas.