Oceans cover most of the planet, but unfortunately, they are highly polluted. To combat this issue, scientists at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart have developed a jellyfish-inspired robot called Jellyfish-Bot. This robot is designed to clean up underwater environments, especially around coral reefs. Unlike existing underwater robots that are bulky and noisy, Jellyfish-Bot is small, versatile, energy-efficient, and nearly noise-free. The researchers published their findings in the journal Science Advances.
Building the Robot
To create Jellyfish-Bot, the team at MPI-IS used electrohydraulic actuators, which are like artificial muscles powered by electricity. The actuators are surrounded by air cushions, as well as soft and rigid components that stabilize the robot and make it waterproof. This prevents the high voltage in the actuators from contacting the surrounding water. Thin wires periodically provide electricity, causing the muscles to contract and expand. This allows the robot to gracefully swim and create swirls underneath its body.
Effective Underwater Propulsion and Manipulation
The researchers explain that when a jellyfish swims upwards, it can trap objects along its path by creating currents around its body. Jellyfish-Bot also circulates the water around it, which is useful for collecting waste particles and fragile biological samples like fish eggs. It can then transport these objects to the surface for recycling. The robot’s interaction with aquatic species is gentle and nearly noise-free, preserving the surrounding environment.
Combating Marine Litter
Approximately 70% of marine litter sinks to the seabed, with plastics making up more than 60% of this waste. The researchers recognize the urgent need for a robot that can manipulate objects, such as litter, and bring them to the surface. They hope that underwater robots like Jellyfish-Bot can assist in cleaning up the world’s oceans.
Features and Future Development
Jellyfish-Bots can move and trap objects without physical contact, either individually or in combination with other robots. They operate faster than similar inventions, reaching speeds of up to 6.1 cm/s, and require low input power of around 100 mW. The robot is safe for humans and fish, even if the insulating material is torn apart. Additionally, Jellyfish-Bot’s noise level is indistinguishable from background levels, allowing it to interact gently with the environment.
The robot is made up of different layers, including stiffening layers, floatation layers, insulating layers, and a floating skin made of polymer material. The middle layer contains electrically powered artificial muscles called HASELs, which resemble real muscles. These muscles can withstand the high electrical stresses generated by the charged electrodes and are protected against water by the insulating layer. The researchers first developed Jellyfish-Bot with a single electrode with six arms and later divided it into separate groups to actuate them independently.
In the future, the researchers aim to develop wireless robots. They have already taken the first step by incorporating functional modules like a battery and wireless communication parts. During their experiments, they successfully steered Jellyfish-Bot in a pond at the Max Planck Stuttgart campus, but they have yet to make the wireless robot change direction.