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About Underwater Swimming Manipulators
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Description Underwater Swimming Manipulators are bio-inspired Autonomous Underwater Vehicles (AUVs) designed to conduct observation and light intervention tasks more economically than Remotely Operated Vehicles (ROVs) and classic torpedo-shaped AUVs. They consist of a series of modules joined together by specific articulated joints to form a flexible body whose length varies according to the number of components, with a diameter usually approximately 10 to 15 cm, which gives them the appearance of a snake or an eel. This design allows them to access narrow spaces where classical ROVs and AUVs cannot enter. They are propelled and guided by thrust devices located at different points along the body. However, their shape also allows them to swim like an eel or a sea snake in case propulsion thrusters are out of service. Note that each module is dedicated to a specific task, such as propulsion and direction, observation (camera and lighting), detection, mapping, and others that can be arranged according to the operator's needs. Tools, such as grippers, pliers, cutters, brushes, and others, can be mounted at the extremities. Like conventional AUVs, Underwater Swimming Manipulators are designed to stay underwater for long periods, provided that a docking station to recharge their batteries, transfer data, and install new programs is available on-site. Note that the docking station is also designed to offer a range of tools that the machine automatically selects and installs. These machines are also easily transportable, so they can be transferred to a site by a small boat or from the facility to which they are assigned. "Eelume", a manufacturer part of the Kongsberg Group, a well- known company that provides a wide range of products and solutions for the maritime industry, appears to be the most advanced project utilizing this technology. The pictures below, taken from the patent file, explain how these machines are designed and some of their capabilities.
#1: Joint module #2: Fins #3: Tunnel thrusters module #4: Stern propeller module #5: The front module of the robot can be provided with a tool, a camera, and various sensors This configuration allows the robot to swim long distances
We can see that their specific design and modularity allow these machines to carry out a wide range of inspections and light interventions on subsea structures. They can also conduct environmental surveys, such as detecting gas leaks, oil in water, water salinity and temperature levels, harmful sound emissions, etc. The machines currently sold are designed to operate at 600 m and range from 15 to about 50 km, which is, in my opinion, sufficient to carry out the tasks they are designed for on the oilfield where the docking station is installed. The Eelume team plans for versions designed for deeper depths. However, their commercialization will depend on the market and requests. Eelume team states that these machines can be mobilized 24/7, regardless of weather conditions, and can reduce the cost of subsea operations by up to 90%. Notwithstanding the manifold benefits of these systems, I lack the means to corroborate this information and opine that ultimate discretion on this matter will rest with the operators. Eelume team also says these robots will replace divers, ROVs, and classical AUVs. However, even though these robots will undoubtedly replace ROVs and AUVs for some tasks, I think they have to be considered more as complementary machines than replacement ones, as they are not powerful enough to carry out many inspection and manipulation tasks. Also, note that they are designed to operate from a docking station that must be installed and maintained, which normally requires ROV or diver interventions that may not be difficult to organize in some locations but more complicated in others. Regarding the replacement of divers, although ROVs and AUVs are indeed used today for many tasks previously carried out by divers, it is worth noting that the Norwegian authorities had intended to discontinue offshore manned diving operations in the 1990s. However, they soon abandoned this plan and focused on developing the NORSOK standard U100. This shift was prompted by the realization that certain tasks could not be carried out as efficiently by remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) as divers, who can straightforwardly execute complex tasks that would otherwise require significant engineering and a lot of time from ROVs and AUVs. In conclusion, these robots should be considered efficient complementary tools to existing systems. However, it is evident that their implementation will result in a reorganization of the underwater tasks in the locations where they will be installed.
#1: Joint module #2: Fins #3: Tunnel thrusters module #4: Stern propeller module #5: The front module of the robot can a tool attached
#1: Joint module #2: Fins #3: Tunnel thrusters module #4: Manipulation Tools #5: Sensors This configuration allows the machine to use two manipulators or other tools (one tool at each extremity). The manufacturer says that this configuration permits operations over short distances only. The tunnel thrusters perform the displacement of the machine.
#1: Joint module #2: Fins #3: Tunnel thrusters module #4: Manipulation Tools #5: Sensors #6: Side mounted thruster (Longitudinal thrust) Another configuration that allows the robot to swim long distances and use tools such as manipulators. Note that rubber envelopes protect the joints.
Contact Eelume Address: Transittgata 10, 7042 Trondheim - Norway Website: https://eelume.com/ Phone: +47 46 500 700 Email: contact@eelume.com
Bibliography • Snake-like Robots - Machine Design of Biologically Inspired Robots Authors: shigeo Hirose, and Hiroya Yamada. Published in 2009 • Modeling of underwater swimming manipulators. Authors: J. Sverdrup-Thygeson, E. Kelasidi, K. Y. Pettersen, J. T. Gravdahl. Published in 2016 • A control framework for biologically inspired underwater swimming manipulators equipped with thrusters. Authors: J. Sverdrup-Thygeson, E. Kelasidi, K. Y. Pettersen, J. T. Gravdahl. Published in 2016 • Experimental Investigation of Locomotion Efficiency and Path- Following for Underwater Snake Robots with and without a Caudal Fin. Authors: E. Kelasidi, A. M. Kohl, K. Y. Pettersen, B. H. Hoffmann, J., and T. Gravdahl Published in 2018 • Fluid parameter identification for an underwater snake robot. Authors: Eleni Kelasidi, Gard Elgenes, and Henrik Kilvaer Published in 2018 • Path Following, Obstacle Detection and Obstacle Avoidance for Thrusted Underwater Snake Robots Authors: Eleni Kelasidi, Signe Moe, Kristin Y. Pettersen, Anna m. Kohl. Published in 2019 • The Underwater Swimming Manipulator – A Bio-Inspired AUV Authors: J. Sverdrup-Thygeson, E. Kelasidi, K. Y. Pettersen, J. T. Gravdahl Published in 2020 • United States Patent - Underwater manipulator arm robot Applicant: Eelume AS Inventors: Kristin Y. Pettersen, Pål Liljebäck, Asgeir J. Sørensen, Øyvind Stavdahl, Fredrik Lund, Aksel A. Transeth, Jan Tommy Gravdahl Published in 2020