Most of the world is covered with oceans, which are unfortunately very polluted. One of the strategies for dealing with piles of waste in these highly sensitive ecosystems, particularly around coral reefs, is to deploy robots to clean them up. However, current divers are often unable to study and sample bulky, rigid-bodied, complex and unstructured environments and are noisy due to electric motors or hydraulic pumps.

For a more viable design, scientists at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart turned to nature for inspiration. They have configured a jellyfish-inspired, versatile, energy-efficient and virtually silent arm-sized robot. Jellyfish-Bot is the result of collaboration between MPI-IS’s Physical Intelligence and Robotic Materials departments. “A versatile robotic jellyfish-like platform for effective underwater movement and manipulation” has been published. Science Advances.

The team used electro-hydraulic drives through which electricity flows to build the robot. Actuators act as artificial muscles that feed the robot. These muscles surround the soft and hard components that stabilize and waterproof the robot, as well as airbags. Thus, the high voltage passing through the actuators cannot come into contact with the surrounding water.

The power supply periodically sends electricity through thin wires, causing the muscles to contract and expand. This allows the artifact to float gracefully and form eddies under its body.

“When a jellyfish swims up, it can catch objects in its path and create currents around its body. This way it can also collect nutrients. Our robot also circulates the water around itself. This function is useful for collecting objects such as waste particles. It can then move the debris to the surface where it can be processed later. It can also be processed.” “It can also collect fragile biological samples such as fish eggs. It also has no negative impact on the environment. The interaction with aquatic species is gentle and almost silent,” explains Tianlu Wang.grati

Co-author Hyun-Jung Joo of Robotic Materials continues: “It is estimated that 70% of marine litter sinks to the seabed. More than 60% of this litter, which takes hundreds of years to decompose, is plastic. Therefore, it will manipulate objects such as litter and “We see an urgent need to develop a robot that can carry upwards. We hope that underwater robots can one day help clean up our oceans.”

Jellyfish boats can move and grab objects without physical contact, acting alone or in a combination of several. Each robot works faster than any other similar invention, reaching speeds of up to 6.1 cm/s. Also, Jellyfish-Bot only requires a low input power of around 100mW.

And if one day the polymer material that insulates the robot breaks, it’s safe for humans and fish. At the same time, the noise from the robot is indistinguishable from the background level. In this way, Jellyfish-Bot interacts gently without interfering with the environment, just like its natural counterpart.

The robot consists of several layers: some make the robot more rigid, others serve to sustain or insulate it. Another layer of polymer acts as a floating shell. Electric artificial muscles known as HASELs are placed in the middle of the various layers. HASELs are plastic bags filled with liquid dielectric partially covered with electrodes. Applying a high voltage to the electrode charges it positively, while the surrounding water is negatively charged.

This creates a force between the positively charged electrode and the negatively charged water that pushes the fat inside the sacs back and forth, causing the sacs to contract and relax like a real muscle. HASELs can withstand high electrical voltages created by charged electrodes and are protected from water by an insulating layer. This is important because HASEL muscles have never been used to build an underwater robot before.

The first step was to develop a single-electrode Jellyfish-Bot with six fingers or hands. In the second step, the team separated the single electrode into separate groups to independently activate.

“We made it grasp objects with four arms acting as screws and the other two as clamps. Or we operated only part of the arms to steer the robot in different directions. We also explored how we could control a group of several robots. For example, we took two robots and it was very difficult for a robot. “We let them match the mask. Both robots can work together to carry heavy loads. But for now our Jellyfish-Bot needs a wire. That’s a disadvantage if we really want to use it once in the ocean,” says Hyun-Jung Joo.

Perhaps the wires that power the robots will soon be a thing of the past. “We aim to develop wireless robots. Fortunately, we have taken the first step towards this goal. We have included all functional modules such as batteries and wireless components to enable wireless manipulation in the future,” continues Tianlu Wang.

The team attached the flotation unit to the top of the robot, and the battery and microcontroller to the bottom. They then swam with their invention in the pond of the Max Planck campus in Stuttgart and were able to run it successfully. But so far they have not been able to direct the wireless robot to change course and swim in the other direction. Getting to know the team, achieving this goal will not take long.