Washington (ISJ) – An Indian engineering researcher at Massachusetts Institute of Technology (MIT) has developed a football size robot which can skim discreetly along a ship hull to seek hollow compartments concealing contraband. The robot was unveiled at the International Conference on Intelligent Robots and Systems by Sampriti Bhattacharyya, a graduate student in mechanical engineering at MIT.
Sampriti, who hails from Kolkata, India, designed the robot initially to look for cracks in nuclear reactors’ water tanks, but later found it could also be used to inspect ships for false hulls and propeller shafts that smugglers frequently use to hide contraband. The robot, a little smaller than the size of a football, with a flattened panel on one side can slide along an underwater surface to perform ultrasound scans. Due to its size and unique propulsion mechanism ? which leaves no visible wake ? the robot 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 a 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, 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.”
Sampriti 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.
The elliptical shape of the robot, though inherently unstable, gives the flexibility in movement.
“It’s very similar to fighter jets, which are made unstable so that you can manoeuvre them easily,” she says. “If I turn on the two jets [at one end], it won’t go straight. It will just turn.”
In the robot’s watertight chamber are its control circuitry, its battery, a communications antenna, and an inertial measurement unit, which consists of three accelerometers and three gyroscopes that can gauge the robot’s motion in any direction. The control algorithm constantly adjusts the velocity of the water pumped through each of the six jets to keep the robot on course.
In their initial experiments, the researchers were just testing the robot’s ability to navigate to an underwater surface and stay in contact with it while traveling in a straight line, so the prototype is not yet equipped with an ultrasound sensor.
The rechargeable lithium batteries used in the prototype, Sampriti says, last about 40 minutes. Since the robot can travel between half a meter and a meter per second while pressed against a surface that should give it ample time to inspect multiple small craft before being recharged. The researchers envision that teams of the robots could be kept in rotation, some returning to port to recharge just as others are going back on duty.
Their next prototype, she says, will feature wirelessly rechargeable batteries. And modifications to the propulsion system that should increase the robot?s operation time on a single charge to 100 minutes.
Nathan Betcher, a special-tactics officer in the U.S. Air Force, who followed the work of Sampriti and Asada?s closely says, ?I have a great deal of interest in seeing if this type of technology can have a substantive impact on a number of missions or roles which I might be charged with in the future.? ?I am particularly interested to see if this type of technology could find use in domestic maritime operations ranging from the detection of smuggled nuclear, biological, or chemical agents to drug interdiction, discovery of stress fractures in submerged structures and hulls, or even faster processing and routing of maritime traffic.?
Sampriti, alongwith some of friends have set up LabX Foundation, an organisation that aims to ?create first of its kind structured programme that connects hundreds of small engineering schools in India?. LabX in its website claims, it aims to build within the Indian community in the US, a strong foundation of scientists and entrepreneurs who are both able and motivated to create changes in their communities.
