This 3D-printed origami trap captures delicate sea life without hurting them

This 3D-printed origami trap captures delicate sea life without hurting them

July 19, 2018 0 By Nazmul Khan

To call someone “spineless” is an insult on land, but in the ocean, it’s simply a sensible lifestyle choice. From jellyfish to octopuses, anemones to sea cucumbers, life under the waves teems with squishy invertebrates. But while these soft bodies are perfectly adapted to the crushing pressures of the ocean, they present a problem for scientists who are hoping to study them. How do you retrieve such delicate organisms without damage?

One answer might lie in the Japanese art of origami. Inspired by the traditional paper-folding techniques, engineers and marine biologists have designed a 3D-printed, 12-sided origami trap that can fold gently around unsuspecting sea creatures. The device (known as the rotary actuated dodecahedron, or RAD for short) can be attached to the arm of an underwater rover and triggered remotely to capture soft marine life safely.

The device has already been tested successfully, trapping small squid, octopuses, and jellyfish at a depth of 700 meters in the ocean. But its design is robust enough to work at depths of up to 11 kilometers, and it could easily be scaled up to target larger organisms.

David Gruber, a marine biologist who helped design RAD, told The Verge that new technology like this is key to exploring the ocean. Beginning in the 1920s, attempts to study marine life relied on nets that successfully trawled the seas for hard-bodied species like fish and crustaceans. They were indiscriminate in what they captured, however, and they shredded gelatinous lifeforms. New devices like suction samplers (which literally hoover up samples from remote rovers) can target a specific organism, but they can still damage delicate lifeforms.

Still images showing the capture of three different types of soft-bodied sea life using the RAD.
Image: Wyss Institute at Harvard University

This means that the study of soft-bodied creatures like jellyfish, comb jellies, and tunicates has been “neglected,” says Gruber. They’re even referred to as the “forgotten fauna” for this reason. Gruber says with the help of new technology, we are just beginning to understand the vital role such creatures play in the ocean ecosystem. “Globally, gelatinous zooplankton are estimated to constitute a biomass of more than 38 billion kilograms of carbon,” he points out. That’s roughly 7 percent of the world’s total biomass (the dry weight of living organisms), or more than 100 times the total biomass of humanity.

Designing the RAD wasn’t easy, though, and the device is full of small but important design touches. For example, there are gaps left between the panels of the dodecahedron in order to stop pressure from building up in the interior when the marine rover makes the trip from the ocean floor to the surface. The edges of these panels are also softer than the durable plastic of the main body. (This decision was made so that the device doesn’t accidentally amputate any sea creatures that fight to get out.)

But according to Harvard University mechanical engineer Zhi Ern Teoh, the key challenge was getting the origami to unfold using just a single motor. Doing so means that the whole system has fewer points of failure and can be folded and unfolded with a single command. But it meant Teoh and his peers had to design a complex series of linkages that connects each of the device’s 12 panels back to the central motor. These had to be light enough not to strain the motor and robust enough not to break mid-mission.

Lead author of the research, Zhi Ern Teoh, inspects the RAD when attached to an underwater rover (left) and a close-up of the RAD, folded shut (right).
Photo by Kaitlyn Becker / Wyss Institute at Harvard

This origami device is just one method that’s being explored for the capture of soft-bodied marine life. Other scientists have experimented with robot hands made from squidgy fingers that are perfect for grasping coral. But one big advantage of this new design, say Teoh and Gruber, is its potential for modification.

As mentioned above, the basic origami mechanism could be scaled up to just about any size, allowing it to capture larger species. (Teoh says a human-sized version could even be used for self-erecting habitats in space exploration.) While the RAD is currently manually operated, it could also be turned into an automated trap with lures to attract sea creatures and sensors to detect when they’re in the right position to be grabbed.

Gruber is even more ambitious. “I view this as a platform technology that we hope will continue to evolve,” he says. “The dream is to enclose delicate deep-sea animals, take 3D imagery that includes properties like hardness, 3D-print that animal at the surface, and also have a ‘toothbrush’ tickle the organism to obtain its full genome. Then, we’d release it.”

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