Robotics engineers at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart have developed a jellyfish-inspired underwater robot, which they hope will one day help clean up oceans by collecting debris, wastr and plastics.
The prototype developed by the team is reportedly nearly noiseless and is designed to capture objects underneath its body without physical making contact. This feature was implemented to minimise its impact on delicate environments, such as coral reefs.
Other environmental remediation projects have sought to use robotics solutions to clean up marine environments, such as a microplastic-absorbing fish developed by roboticists in China.
The team at the Max Planck Institute believe that many existing underwater robots are bulky with rigid bodies, meaning they are unable to explore and sample in complex and unstructured environments. They also create noise distribution for marine wildlife due to their use of electrical motors or hydraulic pumps.
To combat some of these challenges, the team in Stuttgart constructed a jellyfish-inspired robot the size of a human hand, dubbed ‘Jellyfish-Bot’.
A paper concerning the robot, named “A Versatile Jellyfish-like Robotic Platform for Effective Underwater Propulsion and Manipulation” was published in Science Advances on April 12, 2023.
The build the bot, the team used electrohydraulic actuators through which electricity flows. The actuators serve as artificial muscles which power the robot. The bot also features HASELs, which are vegetable oil filled plastic pouches that are partially covered by electrodes.
These ‘muscles’ are then surrounded by air cushions, as well as soft and rigid components that work to stabilise the robot and make it waterproof. This way, the high voltage running through the actuators cannot come into contact with the surrounding water.
Small wires provide electricity to make the muscles contract and expand, thereby allowing the robot to swim.
“When a jellyfish swims upwards, it can trap objects along its path as it creates fluid flows around its body. In this way it can also collect nutrients,” said Tianlu Wang, postdoctoral student in the Physical Intelligence Department at MPI-IS and first author of the publication.
“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. Meanwhile, there is no negative effect on the surrounding environment. The interaction with aquatic species is gentle and noise-free.”
Co-author of the paper Hyeong-Joon Joo, from the Robotic Materials Department, added: “[Some] 70% of marine litter is estimated to sink to the seabed. Plastics make up more than 60% of this litter, taking hundreds of years to degrade.
“Therefore, we saw an urgent need to develop a robot which can manipulate objects such as litter and transport it upwards. We hope that underwater robots could one day assist in cleaning up our oceans.”
The bots top speed is 6.1 cm/s, according to its developers, who also claim that robot also requires a ‘low’ input power of about100 mW. And it is safe for humans and fish should the polymer material insulating the robot one day tear apart.
The first step was to develop Jellyfish-Bot with one electrode with six fingers or arms. In a second step, the team divided the single piece of electrode into groups of two and four.
To enable wireless manipulation of the bot, the team incorporated functional equipment such as battery and wireless communication modules. The team likewise attached a buoyancy unit at the top of the robot and a battery and microcontroller to the bottom, before testing the robot in Stuttgart campus’ pond.
