Underwater robot for port security

Football-size robot can skim discreetly along a ship’s hull to seek hollow compartments concealing contraband

Last week, at the International Conference on Intelligent Robots and Systems, MIT researchers unveiled an oval-shaped submersible robot, a little smaller than a football, with a flattened panel on one side that it can slide along an underwater surface to perform ultrasound scans.

Originally designed to look for cracks in nuclear reactors’ water tanks, the robot could also inspect ships for the false hulls and propeller shafts that smugglers frequently use to hide contraband. Because of its small size and unique propulsion mechanism — which leaves no visible wake — the robots could, in theory, be concealed in clumps of algae or other camouflage. Fleets of them could swarm over ships at port without alerting smugglers and giving them the chance to jettison their cargo.

“It’s very expensive for port security to use traditional robots for every small boat coming into the port,” says Sampriti Bhattacharyya, a graduate student in mechanical engineering, who designed the robot together with her advisor, Ford Professor of Engineering Harry Asada. “If this is cheap enough — if I can get this out for $600, say — why not just have 20 of them doing collaborative inspection? And if it breaks, it’s not a big deal. It’s very easy to make.”

Indeed, Bhattacharyya built the main structural components of the robot using a 3-D printer in Asada’s lab. Half of the robot — the half with the flattened panel — is waterproof and houses the electronics. The other half is permeable and houses the propulsion system, which consists of six pumps that expel water through rubber tubes.

Two of those tubes vent on the side of the robot opposite the flattened panel, so they can keep it pressed against whatever surface the robot is inspecting. The other four tubes vent in pairs at opposite ends of the robot’s long axis and control its locomotion.

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