3D-Printed Robot Can Self-Assemble and Roll Out

Soft robots aren’t necessarily a new technology, as scientists and engineers have been developing soft platforms for the better part of a decade. Some prefer to design pliable bots inspired by nature, such as the University of Bristol’s computer-controlled softworm robot, while others utilize bacteria like E. coli.

Others favor a more creative approach, taking inspiration from the Japanese art form of origami, including a team from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Caltech, who have used the art to build a robot capable of moving and changing shape in response to external stimulation.

Known as “Rollbots,” the researchers designed their soft robots using liquid crystal elastomers that deform and change shape when exposed to heat. They have also 3D printed two types of soft hinges that fold at different temperatures- meaning they can be programmed to fold in specific orders, denoting how it will change shape. The passively-controlled Rollbots do not need to be tethered and start as flat sheets measuring out at 8cm long and 4cm wide.

When placed on a hot surface at about 200 degrees Celsius, one set of hinges contorts the robot into a pentagonal wheel, while other sets- on each of the five sides of the wheel, fold when encountering the same heat, thus propelling the Rollbot forward. The engineers created another device that functions similarly, capable of folding itself into the shape of a paperclip when heated, and back again when cooled.

The liquid crystal elastomers the researchers used for the Rollbots don’t necessarily need to rely on heat to change shape, as the material can also be programmed to react to light, pH, humidity, and other stimuli. The team states that they can use the responsive polymers in an architected composite to perform even more complex tasks, or used in other applications such as mobile environmental sensors, or used for exploration.