ROBERT SIEGEL, HOST:
Termites don't have a very good reputation. They conjure images of terrifying wood-munching insects that can take down a house. But in Africa and Australia, termites are better known for their feats of construction rather than destruction. Termite colonies can build huge, elaborate mounds that rise up from the ground like insect skyscrapers.
As NPR Nell Greenfieldboyce tells us, scientists recently took some lessons from termites to design a team of robot construction workers.
NELL GREENFIELDBOYCE, BYLINE: Some insects are good at building things, think of a wasp's nest or an underground labyrinth of ant tunnels. But Justin Werfel says those insect homes are nothing compared to a big termite mound.
JUSTIN WERFEL: Termites are the real masters of construction in the insect world. The largest termite mound on record was 42 feet tall.
GREENFIELDBOYCE: He says each mound has a complicated network of tunnels inside. The overall shape of the amount depends on the species.
WERFEL: Some of them have an open chimney in the center and hot air can come rising out of that. Some of them are closed mounds. There are what are called cathedral mounds, they have all these elaborate ridges on the outside like flight buttresses.
GREENFIELDBOYCE: Millions of insects were together to build these complex, large-scale structures by doing stuff like pushing bits of mud around. And yet they're not following a blueprint or listening to orders from some termite supervisor. Instead, they seem to sense what's around them and apply some simple rules to decide what to do next. That's what inspired Werfel and his colleagues at Harvard University to create robot termites.
WERFEL: We've created this system of multiple independent robots that build things we ask for. And they do it more like the way insects act than the way that robots normally act.
GREENFIELDBOYCE: The robots don't look like termites. They look more like black, mechanical beetles. They're about eight inches long. They have just a few onboard sensors that let them navigate around a work site set up in a lab. Each robot can grab a specially-designed square brick, carry it on its back, and then set it down. Werfel says that he and his team program the robots to follow some simple rules.
WERFEL: They build things that are much larger than themselves. They climb on what they are working on building to get to higher places, and they coordinate what they are doing using a tool that termites use. Rather than talk to one another directly, they coordinate indirectly by changing their shared environment. So one puts down some material, another one comes along and reacts to that material, and uses that to help it decide later whether to put more material down.
GREENFIELDBOYCE: The termite-inspired robots are described in the journal Science. Researchers show how programming the robots to follow different sets of rules can produce a variety of structures, from castles to pyramids. So far, the robots have only made modest structures and they do it slowly. For example, they built one that's shaped like a trident.
WERFEL: And that involves only eight bricks and that takes half an hour.
GREENFIELDBOYCE: The vision is that, someday, swarms of robots could stack up sandbags to protect against flooding, or go to Mars and build living quarters for astronauts. That's still a long way off. But this study is a proof of principle that robots can work together like termites to build complex structures.
And Hod Lipson says that's a big deal. He's an engineer at Cornell University who specializes in robotics.
HOD LIPSON: It's one of these things where the idea has been around for a while, that you can have robots cooperate to construct something larger than themselves, but no one has really been able to get that to work. And it's not because of any specific detail, but it's sort of coordinating everything together.
GREENFIELDBOYCE: He thinks this study opens up a lot of new possibilities for thinking about how to use machines as builders in the future.
Nell Greenfieldboyce, NPR News.
SIEGEL: This is NPR News.