Ants, schooling fish and flocking birds all have something in common – they can achieve things by working together that they could never do on their own. With that in mind, researchers are now looking into ways of allowing "swarms" of communicating robots to accomplish tasks that are difficult or even impossible for single robots. Harvard University recently performed an unprecedented demonstration of that behavior, in which a batch of over 1,000 tiny Kilobots arranged themselves into a variety of pre-assigned two-dimensional shapes.

Each individual Kilobot is only about the diameter of a US quarter-dollar coin, and moves via three rigid legs that are vibrated by two motors, allowing it to move left, right or straight forward. A bottom-mounted wide-angle infrared transceiver shoots a light beam down at the smooth surfaces that the robot shimmies across, that beam reflecting up to be received by other nearby Kilobots. This lets them communicate with one another, and judge proximity to their neighbors. An onboard microcontroller allows them to act on commands they receive from a pulsating overhead infrared light.

Previously, Harvard had demonstrated what a group of 100 of the robots could do when working toward a common goal. This included things like transporting objects to which they were connected, or collectively moving toward a light source.

In the latest experiments, the number of Kilobots was bumped way up to 1,024.

That said, each shape started with a base of just four of the robots. The other Kilobots then assembled around them, acting on commands to form shapes such as that of a starfish, or the letter K. In order to do so, they utilized simple behaviors such as following the edge of a group, tracking their distance from a starting point, and maintaining a sense of location relative to one another.

Problems like traffic jams and off-course robots did sometimes occur, but the adjacent robots detected such situations and worked together to compensate for them.

The Kilobots themselves are designed primarily to be lab tools, so that lessons learned with them can subsequently be applied to groups of larger, more practical robots performing tasks in the real world. "Increasingly, we’re going to see large numbers of robots working together, whether it’s hundreds of robots cooperating to achieve environmental cleanup or a quick disaster response, or millions of self-driving cars on our highways,” said Prof. Radhika Nagpal, in whose lab the swarm was created. "Understanding how to design 'good' systems at that scale will be critical."

A paper on the research was published today in the journal Science.

You can see the swarm in action, in the video below ... and if you'd like to have your own army of Kilobots, you can buy a batch of 10 for under US$1,200.

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