New caterpillar-like robot can climb slopes, transport loads

Scientists have developed a tiny bioinspired soft robot capable of mimicking caterpillar gaits in natural scale, that can climb slopes, squeeze through narrow slits and transport loads.

The 15-millimetre long soft robot harvests energy from green light and is controlled by spatially modulated laser beam. Researchers at the University of Warsaw in Poland used liquid crystal elastomer technology to develop the robot.

For decades scientists have been trying to build robots mimicking different modes of locomotion found in nature.

Most of these designs have rigid skeletons and joints driven by electric or pneumatic actuators.However, a vast number of creatures navigate their habitats using soft bodies. Earthworms, snails and larval insects can effectively move in complex environments using different strategies.

Previous attempts to create soft robots were limited to larger scale (typically tens of centimetres), mainly due to difficulties in power management and remote control.

Liquid Crystalline Elastomers (LCEs) are smart materials that can exhibit large shape change under illumination with visible light.
With the 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.

Researchers, including those from European Laboratory for Non Linear Spectroscopy (LENS) in Italy and Cambridge University (UK), developed a natural-scale soft caterpillar robot with an opto-mechanical liquid crystalline elastomer monolithic design.

The robot body is made of a light sensitive elastomer stripe with patterned molecular alignment. By controlling the travelling deformation pattern the robot mimics different gaits of its natural relatives.It can also 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.

“Designing soft robots calls for a completely new paradigm in their mechanics, power supply and control. We are only beginning to learn from nature and shift our design approaches towards these that emerged in natural evolution,” said Piotr Wasylczyk from University of Warsaw, who led the project.

Researchers hope that rethinking materials, fabrication techniques and design strategies should open up new areas of soft robotics in micro- and millimetre length scales, including swimmers (both on-surface and underwater) and even fliers.