European researchers have demonstrated a bioinspired micro-robot capable of mimicking caterpillar gaits in natural scale.
The 15 mm soft robot uses liquid crystal elastomer (LCE) technology, harvests energy from green light and is controlled by spatially modulated laser beam.
LCEs are smart materials that can exhibit large shape change under illumination with visible light. Using recently developed techniques, it is possible to pattern these soft materials into arbitrary three dimensional forms with a pre-defined actuation performance. The light-induced deformation allows a monolithic LCE structure to perform complex actions without numerous discrete actuators.
By controlling the travelling deformation pattern the robot mimics different gaits of its natural relatives. It can walk up a slope, squeeze through a slit and push objects as heavy as ten times its own mass, demonstrating its ability to perform in challenging environments and pointing at potential future applications.
The project leader was Piotr Wasylczyk, head of the Photonic Nanostructure Facility at the University of Warsaw.
"Designing soft robots calls for a completely new paradigm in their mechanics, power supply and control," said Wasylczyk.
"We are only beginning to learn from nature and shift our design approaches towards these that emerged in natural evolution."
The work was done in collaborations with Cambridge University and the LENS Institute from the University of Florence, which originally developed the LCE technology.
Wasylczyk says that most of the work done trying to build robots that mimic different modes of locomotion found in nature have focussed on rigid skeletons and joints driven by electric or pneumatic actuators. However, a vast number of creatures such as earthworms, snails and larval insects can effectively move in complex environments using different strategies.
He hopes that rethinking materials, fabrication techniques and design strategies should open up new areas of soft robotics in micro- and millimeter length scales, including swimmers (both on-surface and underwater) and even fliers.
[The caterpillar micro robot sitting on a fingertip. Photo: University of Warsaw]