The Jellyfish-Bot in an underwater experiment with fluorescein dye. PHOTO/Science Advances
By PATRICK MAYOYO
Scientists have developed an underwater robot (bot) they hope will be cleaning up human-caused pollution in the ocean a new study published in Science Advances says.
Scientists at Max Planck Institute for Intelligent Systems (MPI-IS) hope their innovation dubbed Jellyfish, a robotic (bot) device that resembles a jellyfish that could help pick up pollutants underwater.
The robot is about the size of a hand. 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,” the scientists say.
They add that using the platform, they 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,” they noted.
Electrohydraulic actuators resemble muscles in the robot, and these “muscles” are protected and waterproofed by air cushions and other parts. The artificial muscles, called HASELs, can contract and expand, allowing the robot to move through the water. Like a real jellyfish, the robot’s movements create currents beneath it. Jellyfish use the currents to collect nutrients, while Jellyfish-Bot uses these motions to trap pollutants.
“It is also able to collect fragile biological samples such as fish eggs. Meanwhile, there is no negative impact on the surrounding environment. The interaction with aquatic species is gentle and nearly noise-free,” Tianlu Wang, a postdoctoral researcher at MPI-IS and first author of the study, explained in a statement EcoWatch says.
The robots move at a speed of 6.1 centimeters per second, trapping objects along the way, whether it’s a single robot or multiple robots working together. With larger objects, it may require at least two robots to collect and bring the items to the surface for recycling.
According to the researchers, the robot is no louder than background noise, so it shouldn’t disrupt sea life. The insulating polymer shell around the robot shouldn’t harm humans or fish if it were to be torn apart, although the scientists are also open to using newer materials, like self-healing or biodegradable polymers, for the shell in the future.
For now, the robots are powered by thin wires, which prohibits their practical use in oceanic settings. So far, the team has tested a wireless version of the robot with a buoyancy unit, a battery and a microcontroller, although the robot wouldn’t respond to commands to swim in different directions. But the scientists are continuing to test other options and hope that they can achieve a wireless Jellyfish-Bot.
“Seventy percent 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 to manipulate objects such as litter and transport it upwards,” Hyeong-Joon Joo, study co-author and member of the Robotic Materials Department at MPI-IS, said.
Hyeong-Joon Joo said they hope that underwater robots could one day assist in cleaning up our oceans.
