Justin Werfel, Yaneer Bar-Yam, and Radhika Nagpal, Construction by robot swarms using extended stigmergy, AI Memo AIM-2005-011 (MIT Computer Science and Artificial Intelligence Lab, 2005).
We describe a system in which simple, identical, autonomous robots assemble two-dimensional structures out of identical building blocks. We show that, in a system divided in this way into mobile units and structural units, giving the blocks limited communication abilities enables robots to have sufficient global structural knowledge to rapidly build elaborate pre-designed structures. In this way we ex- tend the principle of stigmergy (storing information in the environment) used by social insects, by increasing the capabilities of the blocks that represent that en- vironmental information. As a result, arbitrary solid structures can be built using a few fixed, local behaviors, without requiring construction to be planned out in detail.