US scientists create prototype of autonomous origami-inspired robot

Sunday, August 10, 2014

Self-folding crawling robot in three stages.
Image: Seth Kroll, Wyss Institute.

A research team from the Massachusetts Institute of Technology (MIT) and Harvard University's Wyss Institute for Biologically Inspired Engineering has developed a robot that assembles itself within four minutes from a flat sheet into a 3D (three-dimensional) moving structure. Unlike previous self-folding machines, the robot can function autonomously. Science published the study this Friday.

Also on Friday, Science published a report of a Cornell University-led research team on applications of origami in design of programmable metamaterials.

As The Guardian reported, MIT–Harvard team lead author Sam Felton, a Harvard University Ph.D. candidate, priced the manufacturing equipment for the robot at $3,000, which could then make each individual unit — a 13cm-long, Transformer-like robot — for about $100.

As described by MIT researchers, the initially flat sheet consists of five layers: copper wires in the middle, then two layers of paper (above and below), and two outer layers of shape memory polymer. The embedded heating circuits activate the robot's self-folding by heating shape memory polymers at the hinges. The parameters defining the fold pattern which determines the final 3D shape are placement of the self-folding hinges, and the order of their triggering. Felton told about creation of the pattern: "Cyclic folds are used by a software program called 'Origamizer' as building blocks to create any polyhedron. We've discovered that we can [...] create a wide variety of structures and machines."

Once the battery is attached to the design, the robot folds itself into the pre-determined shape and walks away, with motion of the four-legged robot controlled by the included microprocessor and two small motors synchronised by it. Each of the four legs has eight "linkages" which convert the force applied by a motor into motion. "It lets you transfer just one degree of freedom into a whole complicated motion, all through the mechanics of the structure," says coauthor Erik Demaine, MIT professor of computer science and engineering.

The robot moved during testing at about 5.4 centimeters per second, over a pre-determined route, not just a straight line — without any outside assistance. Marc Lavine, a senior Science editor, suggested such robots might be put in place "through a confined passageway, such as a collapsed building, after which they would assemble into their final form autonomously".

The folding pattern studied by the Cornell-led research team is well-known in origami as Miura-ori, whose unusual engineering properties caught the attention of team member Chris Santangelo of the University of Massachusetts Amherst.

Cornell University lead author Jesse Silverberg commented on potential of origami-based engineering: "When incorporated into more complex devices, these materials will enable on-the-fly transformation of mechanical function. We envision combining these origami-inspired materials with computer-controlled actuators to build more complex machines, such as hardening shells, locked-in joints and deployable barriers; and ultimately, this transformer technology will revolutionize the way we think about materials, moving them beyond their current static form, and revealing more functionality than what originally meets the eye".