Robot jellyfish snags plastic prey

Robot researchers have designed a jellyfish-inspired robot to help clean up the ocean waste, particularly litter on the ocean floor.

The world’s oceans are polluted with plastic, so why not send a robot made from the stuff to clean it up?

The jellyfish-bot is about the size of a human hand. It’s quiet, energy efficient and designed to collect waste from the seabed and bring it to the surface. 

The research was done at the Max Planck Institute in Germany.

“When a jellyfish swims upwards, it can trap objects along its path as it creates currents around its body. Our robot, too, circulates the water around it. This function is useful in collecting objects such as waste particles. It can then transport the litter to the surface, where it can later be recycled,” says Tianlu Wang, lead author of the paper published in Science Advances.

Underwater robots often take their inspiration from sea creatures. Researchers from Zhejiang University in China created a robot based on a deep-sea snailfish to navigate the bottom of the Mariana Trench. Harvard University researchers created ‘Bluebots’, small fish-inspired robots that can both swim independently and synchronise their movements to imitate schooling behaviour. Virginia Tech researchers created an ‘Octa-glove’ to help humans pick up slippery objects underwater.

The jellyfish robot’s ‘tentacles’ use electrohydraulic actuators which work like artificial muscles powered by electricity. 

These are surrounded by materials designed to stablise and waterproof the robot so the electricity doesn’t come into contact with surrounding water. But the researchers say, even if the insulating material was torn, the low power input would remain safe for humans and sea creatures.

As the ‘muscles’ contract and expand, the robot swims gracefully and creates swirls underneath its body, moving and trapping objects.

“We achieved grasping objects by making four of the arms function as a propeller, and the other two as a gripper. We also looked into how we can operate a collective of several robots. For instance, we took two robots and let them pick up a mask, which is very difficult for a single robot alone,” co-author Hyeong-Joon Joo says.

At present the robot’s design is wired, meaning power is supplied to the robot jellyfish by a thin cable. The researchers are now working on making their design wireless.