Engineers at Northwestern University developed the smallest-ever remote-controlled walking robot, and it takes the form of a peekytoe crab.
The crab robot is smaller than a flea, measuring just half a millimeter in diameter. Even so, it can bend, twist, crawl, walk, turn, and jump, all while being remotely controlled. And it's all thanks to the culmination of research into submillimeter-scale multimaterial terrestrial robotics, which the Northwestern engineering team just published a paper about.
The robot is constructed of shape-memory alloy material capable of transforming to a "remembered" shape when heated. A laser is used to rapidly heat a thin coating of glass on the robot which returns it to the remembered shape, and then it deforms as it cools allowing for locomotion to occur.
The scanning direction the laser is applied to the surface determines the direction of travel, and because the robot structure is so small, cooling happens very quickly allowing it to "run faster." As to how fast the little crab can move, the average speed is half its body length per second.
Constructing the robot is achieved using a pop-up method inspired by children's pop-up books. The different parts are fabricated flat, then bonded together on a slightly stretched rubber substrate. When allowed to relax, the crab pops up into a predefined three-dimensional state/shape.
It's possible to fabricate these simple robots at any size and using any 3D shape, but what can they be used for? According to John A. Rogers, one of the engineers at Northwestern's McCormick School of Engineering and Applied Science, "You might imagine micro-robots as agents to repair or assemble small structures or machines in industry or as surgical assistants to clear clogged arteries, to stop internal bleeding or to eliminate cancerous tumors — all in minimally invasive procedures."