MIT engineers say they've created a miniature device that can fold itself up into amost any shape, opening the way for cheap, reconfigurable robots.
The caterpillar-sized assembly of metal rings and strips is called a milli-motein and designed to mimic proteins, which naturally fold themselves into incredibly complex shapes.
"It's effectively a one-dimensional robot that can be made in a continuous strip, without conventionally moving parts, and then folded into arbitrary shapes," says Neil Gershenfeld, head of MIT's Center for Bits and Atoms.
It has a new kind of motor: small, strong and able to hold its position firmly even with power switched off. The electropermanent motor is similar in principle to the giant electromagnets used in scrapyards to lift cars, in which a powerful permanent magnet is paired with a weaker magnet whose magnetic field direction can be flipped by an electric current in a coil.
The two magnets are designed so that their fields either add or cancel, depending on which way the switchable field points.
In the new miniature version, a series of permanent magnets paired with electromagnets are arranged in a circle and drive a steel ring around them. They don't take power in either the on or off state, but use power only in the changing state.
"This result brings us closer to the idea of programmable matter - where computer programs and materials merge to form a new kind of matter whose shape and function can be programmed - not unlike biology," says Hod Lipson, an associate professor of mechanical and aerospace engineering and computing and information science at Cornell University.
"Many people are excited today to learn about 3D printing and its ability to fabricate any shape; Gershenfeld's group is already thinking about the next episode, where we don't just control the shape of objects, but also their behavior."
The milli-motein is part of a family of devices, ranging from protein-based 'nanoassemblers' to a version where the chain is as big as a person. Ultimately, says the team, the work could lead to robotic systems that can be dynamically reconfigured to do many different jobs rather than repeating a fixed function, and that can be produced much more cheaply than conventional robotics.