Roboticists at the Max Planck Institute for Intelligent Systems (MPI-IS) have designed a jellyfish-inspired robot which can collect waste from the bottom of the ocean. Unlike the underwater robot prototypes currently being tested, these Jellyfish-Bots are noise-free and can trap objects underneath its body without physical contact, thereby enabling safe interactions in delicate environments, such as coral reefs.
The robot prototype consists of a series of six electro hydraulic actuators that serve as artificial muscles which power the robot. Electrically powered artificial muscles – known as HASELs – are essentially liquid dielectric-filled plastic pouches that are partially covered by electrodes. By applying a high voltage across an electrode it positively charges the bot, while surrounding water is charged negatively. This pushes the oil inside the pouches back and forth, causing the actuators to execute their flapping movement. This enables the underwater robot to swim gracefully and create swirls underneath its body.
Jellyfish-Bots can move and trap objects without physical contact, operating either alone or with several in combination. Each robot can reach a speed of up to 6.1 cm/s., and only requires 100mW of electricity, meaning it doesn’t pose any harm to humans or aquatic life. It is also able to execute grasping motions when two of the actuators were brought toward each other. Two robots can work together to pick up more complicated items.
“When a jellyfish swims upwards, it can trap objects along its path as it creates currents around its body,” stated Tianlu Wang, the first author of the publication. “In this way, it can also collect nutrients. 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. 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.”
At this time, Jellyfish-Bots need a wire to operate, but the team is working on modules for the battery and wireless communication parts in order to enable future wireless manipulation.