Email
They have little brains, a dismal work rate, and pay no attention to architects' plans. Rather than looking to humans for inspiration, scientists designing robot bricklayers have learned from termites.
The researchers, at Harvard University, have shown off their first gang of robotic brickies by having them build a small castle. The feat took some time, but marks a leap forward in the design of robots that work together in an ever-changing environment.
Though small, slow and simple, the robots can work without plans to build pre-designed structures. Instead of talking to one another, they all follow the same simple rules drawn up by a computer beforehand.
Autonomous groups of robots that can erect pre-designed buildings could find plentiful work in dangerous places, for example setting up shelters in regions struck by earthquakes, building habitats under the sea, or on distant planets before human missions arrive. They could even stack sandbags to provide flood defences, the US researchers said.
Gangs of robot bricklayers could build habitats under the sea or on distant planets. Photograph: Eliza Grinnell/Harvard School of Engineering and Applied Sciences
"The long-term aim is to build structures autonomously where you cannot easily send people, because the work is either too dirty, too dangerous or too dull," said Justin Werfel at the Wyss Institute for Biologically Inspired Engineering at Harvard. "The robots move very slowly and that's on purpose. They are being very careful about what they do."
Instead of providing all the robots with a plan of the desired building, and appointing a mechanical foreman to direct them, each is given the same set of rules that tells it when to move itself or a nearby brick. The robots – which have wheels and are the size of a toy remote-controlled car – can trundle around, clamber up and down bricks, and lift and lay them. Simple sensors tell the robots when they are next to a brick or another robot.
Central to the work is a computer program that can take the shape of a finished building and turn it into a set of "traffic" rules that are sent to each robot before the job begins. From these rules alone, the robot gangs will move around and place bricks until the structure is complete. Details of the work appear in the journal Science.
The work has impressed other scientists because it shows how teams of robots can be made to work together without having to follow a plan or pass signals between each other. If one robot breaks down, the others will simply work around it. And if an extra robot is added to the team, it joins the effort seamlessly.
The research was inspired by the behaviour of termites, which have minuscule brains but are able to build huge mounds, complete with intricate air-cooling channels. None of the termites has a detailed plan of the mound they are building. Instead they take cues from each other and their surroundings to decide where to lay the next lump of mud.
The rules the robots follow are essentially one-way signs that tell them which direction they must move in. One crucial aspect of the rules ensures that the robots can get on and off the building site without walling themselves in.
In an accompanying article, Judith Korb at the University of Freiburg in Germany, calls the work "extremely elegant". "Humans build houses according to a blueprint, and the construction process is centrally guided by this plan. In contrast, social insects such as termites build in a decentralised, self-organised manner."
The latest work "allows the autonomous construction of any predefined structures with simple robots", she adds.
;