The way worms, caterpillars and snails move fascinates robotics researchers. Their soft bodies are able to move through very complex environments using a variety of different types of movement. There's a whole field devoted to soft robotics, which mimic these movements.

Until recently, most of these soft robots were pretty big - typically tens of centimetres in size - because of the size of components necessary for the robots to manage power and be remotely controlled.

But now a team of robotics engineers at the University of Warsaw have built a robotic caterpillar that's just a few millimetres long.

It can walk along flat surfaces, climb slopes, squeeze through narrow gaps and even transport loads up to ten times its own bodyweight.
Changing shape

They did it using a new type of "smart" materials called Liquid Crystalline Elastomers. These change shape when light is shone on them.

By printing these out into specific forms, it's possible to create devices that move forward in the presence of light. In this case, it's green light that does the job.

But the researchers say that their tiny caterpillar is only the beginning. They believe that by rethinking how we build these types of machines, we'll be able to create robots smaller still - including ones that could swim and fly.
Natural evolution

"Designing soft robots calls for a completely new paradigm in their mechanics, power supply and control," said Piotr Wasylczyk, who led the project.

"We are only beginning to learn from nature and shift our design approaches towards these that emerged in natural evolution."

The research was summarised in a paper in the journal Advanced Optical Materials.