Known as M-Blocks, the cube-shaped robots have no external moving parts, but each contains a flywheel that can reach speeds of 20,000 revolutions per minute. When brakes are applied to the flywheel, it imparts its angular momentum to the cube, causing it to move.
Each M-Block has two cylindrical magnets, mounted like rolling pins on each edge. When two cubes approach each other, the magnets rotate so that north poles align with south and vice versa, allowing any face of any cube to attach to any face of any other. By climbing over and around one another, the cubes can assemble into different shapes.
As with any modular-robot system, the hope is that the cubes can be miniaturised, according to the researchers. The ultimate aim is to create hordes of swarming microbots that can self-assemble, like the “liquid steel” androids in the film “Terminator II.”
In the nearer term, however, the researchers believe that a more refined version of their system could prove useful even at something like its current scale. Armies of mobile cubes could temporarily repair bridges or buildings during emergencies, or raise and reconfigure scaffolding for building projects, for example.
They could also assemble into different types of furniture or heavy equipment as needed. And they could swarm into environments hostile or inaccessible to humans, diagnose problems, and reorganise themselves to provide solutions.
“In the vast majority of other modular systems, an individual module cannot move on its own,” said Kyle Gilpin, postdoc at MIT’s Computer Science and Artificial Intelligence Laboratory. “If you drop one of these along the way, or something goes wrong, it can rejoin the group, no problem.”
Meanwhile, Hod Lipson, a robotics researcher at Cornell University, descibed the M-Block as "a low-tech solution to a problem that people have been trying to solve with extraordinarily high-tech approaches”.
“They showed several modes of locomotion. Not just one cube flipping around, but multiple cubes working together, multiple cubes moving other cubes — a lot of other modes of motion that really open the door to many, many applications, much beyond what people usually consider when they talk about self-assembly," said Lipson.
In ongoing work, the MIT researchers are building an army of 100 cubes, each of which can move in any direction, and designing algorithms to guide them.
“We want hundreds of cubes, scattered randomly across the floor, to be able to identify each other, coalesce, and autonomously transform into a chair, or a ladder, or a desk, on demand,” said MIT research scientist John Romanishin.