Imagine sailing a container ship to help with cleanup at the site of a massive oil spill. Now imagine if each container were actually an autonomous robotic boat. Dumped into the ocean, the boats could link up to form an ad-hoc platform for landing a helicopter or operating a crane.
That’s the aim of DARPA’s Tactically Expandable Maritime Platform, and Engineering professors Vijay Kumar and Mark Yim are leading a Penn team working on the early stages of the project.
Similar to work with the GRASP Lab’s quadrotors, Kumar and Yim are trying to figure out how to give swarms of robots general instructions on how and where to move. The team wants each robot to determine how to best accomplish its task without getting in the way of the other autonomous boats. The researchers have built a fleet of 100 scale model robotic boats, each about a foot-and-a-half long, and are testing them in a pool to improve the algorithms that control this collective behavior.
The boats are labeled with a visual identifier that can be read by a camera, much like a QR code. The camera system feeds location information to each boat’s onboard computer, enabling them to assess where they are in relation to their fleet-mates. Operating in the open ocean with no cameras overhead, the full-size boats will use GPS for their location information.
Once deployed, the researchers only need to provide the boats with a desired final shape, and the robots do the rest.
“We give them a structure, and then each boat figures out where to go and in what sequence to go to make that structure,” Yim says.
Once in place, they connect to one another via a hook-and-tether mechanism, developed by QinetiQ NA, the company that will make the full-sized boats.
Critically, each of these connections can be dynamically tightened and loosened. While the surface of the gymnasium pool where the team is testing the robots is relatively placid, the full-size boats will have to contend with stormy seas and unpredictable conditions. Individual boats need to tightly lock together to allow a vehicle to drive over them, but a totally rigid platform could be broken apart by waves.
“You need to make stiff connections to have a flat surface with no cracks,” Yim says. “So we could tighten only the connections right underneath a vehicle as it’s moving, for example.”
DARPA envisions such a system to be used in dealing with natural and man-made disasters, or in helping deliver humanitarian aid.
Text by Evan Lerner
Video by Kurtis Sensenig