Landing method of autonomous underwater vehicles for seafloor surveying. (August 2020)

• Record Type: Journal Article
• Authors: Matsuda, Takumi; Takizawa, Ryota; Sakamaki, Takashi; Maki, Toshihiro
• Is Part Of: Applied ocean research. Volume 101(2020)
• Publication Date: 2020-08
• Subjects: Autonomous underwater vehicle (AUV) -- Buoyancy control -- Landing -- Seafloor surveying; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2020.102221
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: Landing methods and systems for hovering-type AUVs on the seafloor are proposed. A heading control method, to reduce flow resistance while landing, was implemented. A stability evaluation method using simple time-series attitude data was developed. A buoyancy adjustment system to enhance the landing stability, was developed. The performance of the proposed methods and system were verified through sea tests. Abstract: This paper aims to provide stable landing methods and systems for hovering-type AUVs (autonomous underwater vehicles) on a seafloor, which will aid in seafloor investigations, such as gravity acceleration measurements near the seafloor. The proposed methods consist of two techniques. Firstly, a heading control method is proposed, in which the AUV is positioned to face currents before landing on the seafloor, thus reducing flow resistance. Secondly, a stability evaluation method is proposed, in which the landing quality is evaluated based on fast Fourier transform (FFT) analysis of its attitude. The methods were evaluated and verified based on data obtained from tank and sea experiments using an AUV Tri-TON. Thanks to the stability evaluation method, the landing stability was judged automatically with a success rate of 96% (27 of 28 cases). The heading control method also realized stable landing with a success rate of 80% (4 of 5 cases). To enhance the landing stability further, a buoyancy adjustment system was developed and verified using an AUV Tri-Dog 1. Thanks to the developed system, the stable landing was conducted successfully with a success rate of 100% (4 of 4 cases). The proposed methods and system will contribute to the stable landing of AUVs on the seafloor and enhance future seafloor surveys.