There are several methods of oyster farming, one of which involves raising the molluscs in bags that float on the ocean's surface. Those heavy bags need to be frequently flipped over, so a team of MIT students has designed an "Oystamaran" robot to make the job easier.
Although they're described as bags, the oyster-raising cages are more like flat, square mesh pens with cylindrical floats on two opposite sides.
As the bags sit in the water, marine organisms such as barnacles and algae accumulate on their undersides. Flipping them over exposes those organisms to the sunlight and air, so they can be chipped off once they've dried out. Doing so keeps the organisms from accumulating to the point that they block water flow through the bags, which is essential to the oysters' survival.
The MIT project began when marine biologist Dan Ward – who owns the Ward Aquafarms oyster-farming company in Cape Cod – told Prof. Michael Triantafyllou how the 2,000-plus bags at his farms have to be flipped about 11 times a year. Currently, the task is performed by workers in kayaks, who struggle to keep their balance while flipping bags that can weigh up to 70 lb (32 kg) once the oysters are mature.
Seeking a less labor-intensive alternative, a team of Triantafyllou's ocean engineering students set about developing a bag-flipping robot. Led by Michelle Kornberg (who has since graduated), they created the Oystamaran electric catamaran.
The device starts by straddling a bag between its pontoons. It then uses a hooked robotic arm to reach down and grasp the float on one side of the bag, after which it pulls that arm back up and to the other side, lifting and flipping the bag in the process.
Although the robot presently performs much of its work by real-time remote control, the students are working on making it fully autonomous. It will then use one forward-facing camera to initially identify and make its way over to each bag, after which it will use a downward-facing camera to align itself over the bag and perform the flip.
It is hoped that once developed further – perhaps by an industry partner – the technology could help oyster farmers to increase their output, while also fostering interest in the field of aquaculture robotics.
"Just by showing the way, this may be the first of a number of robots," says Triantafyllou. "It will attract talent to ocean farming, which is a great challenge, and also a benefit for society to have a reliable means of producing food from the ocean."
The Oystamaran can be seen in action, in the following video.
Source: MIT