The ultra-thin, ultra-fast robots that can levitate, swim and catch flies

Robots have a reputation for rigidity but these tiny creations move with the speed and grace of the animals that inspired their design

Researchers in Germany and Austria have created a collection of tiny, ultra-fast robots that can walk, swim, transport cargo, levitate, slip into tiny spaces and capture a fly in the blink of an eye.

The swiftness of these tiny creations is a breakthrough in robotics and could have applications in everything from assembly lines to bio-medics.

“The idea is actually from nature,” said Xu Wang, a material engineer at the Institute of Ion Beam Physics and Materials Research and one of the study’s lead researchers.

“We know that in nature some animals and plants need to act fast, otherwise they cannot survive in harsh environments. For example, if you look at nature, you find Venus flytraps that need to be very fast otherwise the insects just fly away. So we thought, ‘Ok, how can we fabricate a robot that mimics this behaviour?’"

Of the five designs, two can swim and one levitates.

One, shaped like a manta-ray, imitates the flap of fins to glide forward in water. A second swimming robot has a triangular shape and rotates upon itself like a propeller.

Each robot is made of magnetic rubber and is ten times thinner than a human hair. Some are just seven micrometers thick.

It is this thinness that allows such flexible, quick movements. Their soft but durable material, similar to tissue structure, makes them suited for more delicate applications with living organisms.

Hard bodied robots are usually powered by electricity, and reliant on either wires or a battery. But these robots are magnetic and free from cumbersome wires.

“The field of small scale robots is a very intensive research field,” said Denys Makarov, one of the study’s researchers. “It’s much newer than the standard industrial robots and therefore people are still doing a lot of exploration, even answering the question, ‘what can they do’?

“Usually, a robot has a battery or some wires to activate it. In our research, the robot is completely untethered. It is without wires. It’s an achievement because mechanical movement is usually very slow and electronics is fast.

“Our robots are at least one order of magnitude faster than similar robots.”

Their rapid response to changing surroundings gives them the potential to be scaled down for biomedical use in confined environments.

Inspiration for the design came by accident, when a researcher began to play with a piece of rubber on a desk.

“Sometimes you need luck and then you come to a very interesting observation,” said Mr Makarov. “When we saw that you can do much more by simply reducing the thickness, then we thought wow, you can fold it very easily, it’s very compliant and it can be activated in a relatively small magnetic field so it’s energy efficient technology.

“As a scientist, you always try to get something new in your research and I think we did a good job here because we have many models of such a simple object.”

The study was a collaboration between researchers at the Institute of Ion Beam Physics and Materials Research, the Linz Institute of Technology and Johannes Kepler University Linz.

The findings were described in the article Untethered and Ultrafast Soft-bodied Robots, published in Communications Materials on Thursday.

Now that scientists know what is possible, the next step will be adapting the technology to practical applications.

Research began in early 2019 and took a year.

For Mr Xu, validation came after patiently waiting for a fly to land on the petals of a 25mm robot. It all happened so fast, he didn’t know immediately whether his months of research had worked.

"I only saw it after I started to analyse the video and saw, Ok, it really got the fly. At that moment, I was so happy.”

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