A4 androids: Carnegie Mellon researchers 'reinvent paper' to build robots

Often used by children and hobbyists to create miniature aeroplanes, paper could transform into much more advanced engineering thanks to a new technique.

Ordinary paper became robots capable of bending, folding or flattening themselves thanks to the ‘low-cost actuation technology’ from researchers at Carnegie Mellon University in Pennsylvania.

Designing actuators based on the Japanese origami and kirigami techniques, the team created structures capable of transforming into balls or cylinders. More elaborate objects included a lampshade that changes shape to vary the light emitted, and an artificial mimosa plant with leaf petals that open sequentially when one is touched.

"We are reinventing this really old material," said Lining Yao, assistant professor in the Human-Computer Interaction Institute and director of the Morphing Matter Lab at the university, who developed the method with her team. "Actuation truly turns paper into another medium, one that has both artistic and practical uses."

The team 3D-printed a 0.5mm layer of conductive graphene polylactide composite on to plain paper as the actuator. They then heated it in an oven or with a heat gun, bending and folding the paper into a desired shape before letting it cool into its default shape. Electrical leads were then fitted and the operators used the current to heat and expand the actuators, straightening the paper. The devices returned to their default shapes afterwards.

“Most robots – even those that are made of paper – require an external motor," said postdoctoral researcher Guanyun Wang. "Ours do not, which creates new opportunities, not just for robotics, but for interactive art, entertainment and home applications."

The researchers are refining their method, changing the printing speed or the width of the line of thermoplastic to achieve different folding or bending effects. They have also reportedly developed methods for printing touch sensors, finger sliding sensors and bending angle detectors that can control the paper actuators.

Yao and her team hope to speed up the actuation by using more heat-conductive paper and developing customised printing filaments. The same technique could also be used for plastics and fabrics.

For more information, visit https://www.morphingmatter.cs.cmu.edu/.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.