A prototype sheet that folds itself into two different shapes may lead to objects that can assume any number of forms on command
Researchers at Harvard University and the Massachusetts Institute of Technology (M.I.T.) have invented a real-life Transformer, a device that can fold itself into two shapes on command. The system is hardly ready to do battle with the Decepticons—the tiny contraption forms only relatively crude boat and airplane shapes—but the concept could one day produce chameleonlike objects that shift between any number of practical shapes at will.
Self-folding sheets are just one facet of programmable matter, the attempt to build structures that can shape-shift on demand. The idea, says study co-author Daniela Rus, a roboticist at M.I.T., is bringing materials and machines closer together to make everyday objects that can be programmed, much like people program a computer. “Instead of programming bits and bytes,” she says, “you program mechanical properties of the object.”
The system, described in a paper published online this week in Proceedings of the National Academy of Sciences, consists of a thin sheet of resin–fiberglass composite, just a few centimeters across, segmented into 32 triangular panels separated by flexible silicone joints. Some of the joints have heat-sensitive actuators that bend 180 degrees when warmed by an electric current, folding the sheet over at that joint. Depending on the program used, the sheet will conduct a series of folds to yield the boat or airplane shape in about 15 seconds. The folding-sheet approach is an extension of the field of computational origami, the mathematical study of how flat objects can be folded into complex, three-dimensional structures.
Although the design presented in the new paper takes only two shapes, the researchers say that in principle the system could produce many more. “We were looking for ways to embed a bunch of different functionalities into one low-profile sheet,” says study co-author Robert Wood, an electrical engineer at Harvard University’s Microrobotics Laboratory. “In the longer run we’d like to develop systems to bring this not to just three, four or five shapes but to a much greater scope of different achievable shapes.”