If you’ve ever made your own Bristlebot, you can appreciate how pared down and elegant is the category of artificial life know as vibrating robots, or vibrobots. Well, it turns out that when it comes to vibrobots, the whole is greater than the sum of its parts.
In 2011, researchers at Harvard came out with the Kilobot, a tiny, inexpensive ($50 or less) open source research robot that could be controlled en masse using infrared signals. Last week, in the most recent edition of Science (the same journal that featured self-folding walking paper robots), lead author Michael Rubenstein, a research associate in the lab of Radhika Nagpal at Harvard’s School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering, described programming a swarm of Kilobots a thousand strong to arrange themselves in predetermined shapes.
The Kilobots, which resemble a stack of quarters perched on three needle-thin legs, are not that easy to control one on one. Driven by two vibrating motors on opposite sides of their body, they tend to veer off course and misjudge distances.
But when you put 1024 Kilobots in a room (the number corresponds to the number of bits in a kilobyte of information), they work together to complete the assigned task. For instance, to self-organize themselves into a particular shape, four robots mark the origin of a coordinate system, and the rest use primitive behaviors such as following the edge of a group and keeping track of their relative location to wiggle into position. If any stragglers wander away, or a bottleneck forms, other Kilobots step in to bring their fellows back into line.
As the speeded-up video above shows, it can take up to 12 hours for the swarm to whip itself into shape. What makes this newsworthy is the sheer size of the Kilobot collective. While just one of many studying robot swarm behavior, the Kilobot project is the first to include more than just a hundred or so individuals.