ROBOT ARMY TO THE RESCUE

Robot army 'to help future floods'

By Jane Wakefield

Self-organising robots that mimic insect colonies have been shown off by computer scientists at Harvard University.

The robot construction crews could in future be used to help alleviate flooding, building up walls of sandbags or as the construction crew of choice for future building on Mars.

Unlike human construction crews, there is no foreman or central control unit.

Neither is there any need for the robots to communicate with each other.

Dubbed Termes after the termites that build mounds of soil to act as lungs for their underground nests, the robots can build towers and pyramids out of blocks, even constructing their own staircases to reach higher levels.

The team behind the robots, from the Harvard School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering, have taken their inspiration from termite colonies, which demonstrate swarm-like intelligence.

"The key inspiration we took from the termites is the idea that you can do something really complicated as a group without a supervisor, and secondly that you can do it without everybody discussing explicitly what's going on, but just by modifying the environment," said principal investigator Radhika Nagpal, professor of computer science at Harvard SEAS.

Termites rely on a concept known as stigmergy, a kind of implicit communication in which insects observe each others' changes to the environment and act accordingly.

Breakthrough

The robots were designed to do the same. Each robots does its job in parallel with others, but without knowing who else is working at the same time.

It was very different to human construction teams, said lead author Justin Werfel.

"Normally, at the beginning, you have a blueprint and a detailed plan of how to execute it, and the foreman goes out and directs his crew, supervising them as they do it," he said.

"In insect colonies, it's not as if the queen is giving them all individual instructions. Each termite doesn't know what the others are doing or what the current overall state of the mound is."

Currently robotic systems tend to rely either on a central controller that can see the whole process or on all of the robots being able to talk to each other frequently.

The issue with such a system is that if the central controller fails, that will bring down the whole system.

"It may be that in the end you want something in-between the centralised and decentralised system - but we've proven the extreme end of the scale - that it could be just like the termites," said Prof Nagpal.

"And from the termites' point of view, it's working out great."

Prof David Burns, from Aberystwyth university's department of computer science, thinks the robots could represent a breakthrough.

"We have had co-operating robots working in the 2D environment for some time now but for robots to be able to work in the 3D environment, to be able to build things up, is an important step towards the goal of utilising such robots in areas such as construction," he said.

"How do termites produce cathedral-like structures without co-operation? To have a robotic colony acting in a similar way would be a move away from the classic hierarchical structures we used today," he added

The results of the four-year Termes project are published in Science.