Robots use origami to change shape

Tiny autonomous cubes that use origami to change shape could be the key to a new wave of multifunctional robotics, according to research published in the journal Science Robotics.

The tiny cubes, designed and built by a team led by Shuhei Miyashita of the Computer Science and Artificial Intelligence Laboratory at Massachusetts Institute of Technology, in the US, represent a significant advance in the quest to build “self-configuring” robots that can change their functionality by altering their shape.

Earlier designs for self-configuring robots have explored a number of approaches, including having a swarm of bots, each of which makes its own triangular metal mesh to become part of a larger structure, and having robots made from an interchangeable library of modules.

Miyashita and his colleagues point out that these and other approaches share a number of limitations. Many, for instance, are comparatively large, because of the need for each module, or swarm bot, to carry bulky on board electronics.

The team’s solution to these problems is both elegant and – if this is not an inappropriate term to use in relation to industrial robots – cute.

The cube-bots are small – less than a cubic centimetre – because most of the onboard electronics has been ditched. Instead, the bots operate on top of a magnetic base – the pulses of which cause the cube, dubbed a “walkbot”, to move by means of tipping from one face to another.

At a given spot on the magnetic substrate, an electronic plate is positioned, on top of which lies a flat “skin” made of pre-stretched thermo-shrinking polymer film (polyvinyl chloride, in this case). The walkbot moves onto the skin, which is heated by the electronic plate and folds itself, origami-style, around the cube.

At this stage, the original cube has become a robotic object with a more complex shape, and is thus capable of doing a different job. Miyashita’s team show that the process can be repeated, with each origami cover catalysing another, outer layer, to also fold up and form an even more complex form.

In lab tests, each origami metamorphosis took around three minutes.

The process is easy to reverse: once the task of the newly configured robot is over, it is propelled towards a shallow water bath. Beneath the surface, the polymer unfolds and reverts to original flat form, leaving the underlying cube free to head off towards it next job.

“We believe that this work will open the door to the development of a new class of robots that are compact and can be specialized and customized to execute a wide range of tasks,” the authors conclude.