Watch a robot made of robots move around

Good news for small, helpless robots who long to be a part of something bigger: Researchers have found a way to create “robots made of robots” that can move around, even though the individual parts can’t travel on their own.

To create this robot horde, researchers designed several roughly iPhone-size machines called “smarticles”—short for smart particles—that could flap their small arms up and down but could not move from place to place by themselves. They then put five of the smarticles in a plastic ring. This group of robots—which the researchers call a “supersmarticle”—could move by itself in random directions as the individual smarticles collided with each other.

The team then created an algorithm that allowed the supersmarticles to move as a group toward a source of light. Each smarticle was outfitted with a light sensor that caused it to stop moving when it got too bright. When the front robots closest to the bulb stopped moving, the robots in the back, which were in the shadow of the front robots, kept flapping their arms and bumping into each other; they eventually pushed the whole group forward toward the light (see video), the team reports today in Science Robotics.

The researchers suggested that understanding the way the smarticles move together without a central source of control might help scientists design complex robotic systems that can still function even if one part breaks—and could one day be used to create a humanoid robot comprised of many tiny independent parts.