December 6, 2023

Because of the unique way they move through water, jellyfish are often used as inspiration for soft, water-based robots. Now, researchers have discovered that the robotic jellyfish’s flapping propulsion system not only facilitates locomotion, but can also suck up small pieces of debris from the seafloor without any contact. Such robots could be used to remove debris from fragile marine environments such as coral reefs.

The new robot, invented by scientists at the Max Planck Institute for Intelligent Systems (MPI-IS), is about the size of a hand and consists of a series of six actuators filled with artificial muscles called HASEL. These muscles are basically oil-filled sacs covered with electrodes. When the electrodes receive an electric current, they become positively charged. They then release the electrical current into the negatively charged seawater around them. This cycle drives the oil in the bag to push back and forth, causing the actuators to perform their flapping motion.

On top of that, the slapping motion creates a stream of water in the water that can pull the particles up, more or less mimicking the way a plunger pulls a clog out of a drain.

“When a jellyfish swims upstream, it can capture objects along its path as it generates water flow around its body,” said lead author Tianlu Wang, a postdoctoral fellow in the Department of Physical Intelligence at MPI-IS and first author of the publication. “In this way, it can also collect nutrients. Our robot can also circulate water around it. This feature is useful for collecting objects such as waste particles. It can then transport the waste to the surface, where it can be recycled later”

Two jellyfish robots work together to lift their masks while demonstrating one of their other functions
Two jellyfish robots work together to lift their masks while demonstrating one of their other functions

Max Planck Institute for Intelligent Systems

These robots are virtually silent, which, combined with their non-contact approach, makes them an environmentally sensitive tool that can be applied in a variety of situations.

“It’s also capable of collecting delicate biological samples, such as fish eggs,” said Jellyfish-Bot’s Wang. “At the same time, there is no negative impact on the surrounding environment. The interaction with the aquatic species is gentle and almost noiseless.”

While the Jellyfish-Bot can do ocean management without actually grabbing anything, in fact, the researchers were able to demonstrate that when two actuators approach each other in a pincer gesture, the robot can perform a grabbing motion. They also showed that the two robots could work together to lift more complex items, such as face shields, from the ocean floor, as you can see in the video below.

(embed) (/embed)

Jellyfish-like robots could one day clean up the world’s oceans

While the Jellyfish-Bot’s performance is impressive, it does have one serious limitation at this point: it needs to be connected to a wire to get power. However, the research team is working to eliminate this need, and has loaded up a sample robot with batteries and a wireless communication unit and placed it loosely in a pond on the Max Planck campus in Stuttgart. While the robot can move forward, the team couldn’t get it to change course, but it’s working on building that functionality next.

The research has been published in the journal scientific progress.

source: Max Planck Institute for Intelligent Systems