Termite tactics show robots how to build without a plan

Engineers at Harvard University have shown how small robots inspired by termites can build quite elaborate structures, without a centralised plan, by following simple rules of self-organisation.

The project, demonstrated on the opening day of the American Association for the Advancement of Science meeting in Chicago, used wheeled robots to lay plastic bricks in predetermined patterns. The robots were programmed with a few movements to perform under different conditions and given the ability to sense the presence of bricks and other robots. There was no high-level blueprint for the design.

“Termites inspired this whole research topic for us,” said Justin Werfel, lead author of the study, which is published in the journal Science. “We learned the incredible things these tiny insects can build and said: ‘Fantastic, now how do we create and program robots that work in similar ways but build what humans want?’.”

Termites build air-conditioned mounds by taking cues from each other and the environment to tell them where to put the next bit of building material. The Harvard researchers wrote computer programs for their robots to mimic the insects’ behaviour and particularly their use of local information.

Though each robot knows only simple rules – such as when to pick up and put down a brick, turn around or climb one step up the structure – together they act in a quasi-intelligent way capable of completing a predefined structure.

Independent, decentralised robots have the advantage of resilience: “Individual robots can break down but the rest can carry on,” Mr Werfel said. “There is no one critical element that brings everything down if one fails.”

Another advantage is scalability. “For a bigger job you can just add more robots, even mid-job, without needing to change how they are programmed,” he said.

An application of the technology might be to build structures in places where it is dangerous or difficult for people to work, for example shelters after an earthquake or, in the distant future, habitats on other planets.