Jellyfish-inspired robot can gently remove ocean waste without harming marine life

This hand-sized robot moves using electrohydraulic actuators that act as artificial muscles.
Mrigakshi Dixit
Representative image of jellyfish.
Representative image of jellyfish.


Engineers have been inspired by the unique movement of worms, snakes, and jellyfish to develop a new generation of soft underwater robots.

Now, roboticists have created a new robot that can swim like a jellyfish and collect waste from the ocean floor. 

The Max Planck Institute for Intelligent Systems is leading this innovation to clean the world's oceans without harming marine animals and delicate coral reefs.

This jellyfish bot can easily pick up small waste particles

This jellyfish-inspired robot quietly does its job without creating unnecessary noise that could disturb sensitive marine creatures relying on sound to communicate. 

This hand-sized robot moves using electrohydraulic actuators that act as artificial muscles. "We achieved grasping objects by making four arms function as a propeller, and the other two as a gripper. Or we actuated only a subset of the arms, in order to steer the robot in different directions,” said Hyeong-Joon Joo, co-author of this study, in an official release

These artificial muscles are protected by air cushions and soft and rigid material for stability and waterproofing. Electricity is supplied via thin wires to enable swimming, causing the artificial muscles to contract and expand. 

It comprises several layers to improve the robot's performance, such as keeping it stiff when needed, insulated, and afloat. The current speed of the Jellyfish-Bot prototype is approximately 6.1 cm/s, with a power of approximately 100 mW.

The currently used underwater robots are typically bulky, noisy, and harmful to the environment; however, this prototype overcomes these challenges and can easily pick up small waste. This energy-efficient robot can also retrieve delicate samples such as fish eggs or objects like a face mask from the ocean floor. Furthermore, two robots can collaborate to pick up more heavy waste.

Jellyfish-inspired robot can gently remove ocean waste without harming marine life
Team grasping of face mask.

"When a jellyfish swims upwards, it can trap objects along its path and create 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,” said Tianlu Wang, the first author of this study.

Following the creation of this prototype, the team is working to address some limitations, notably the transition from wire to battery or a wireless unit. They will also improve the robot's movement capabilities. 

In the future, a fleet of these underwater robots could help remove waste from deep below, as plastics take hundreds of years to degrade, allowing our oceans and their habitats to breathe again.

The details about this newly built robot have been reported in the journal Science Advances.

Study abstract:

Underwater devices are critical for environmental applications. However, existing prototypes typically use bulky, noisy actuators and limited configurations. Consequently, they struggle to ensure noise-free and gentle interactions with underwater species when realizing practical functions. Therefore, we developed a jellyfish-like robotic platform enabled by a synergy of electrohydraulic actuators and a hybrid structure of rigid and soft components. Our 16-cm-diameter noise-free prototype could control the fluid flow to propel while manipulating objects to be kept beneath its body without physical contact, thereby enabling safer interactions. Its against-gravity speed was up to 6.1 cm/s, substantially quicker than other examples in literature, while only requiring a low input power of around 100 mW. Moreover, using the platform, we demonstrated contact-based object manipulation, fluidic mixing, shape adaptation, steering, wireless swimming, and cooperation of two to three robots. This study introduces a versatile jellyfish-like robotic platform with a wide range of functions for diverse applications.

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