Calendar/2006-4-28

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Title: Thesis Defense: Automating Construction with Artificial Swarms
Speaker(s): Justin Werfel, MIT CSAIL
Time: 2-3pm
Location: MIT, 32-D463 (Star)
Abstract: In this thesis I describe a distributed system for automating construction, in which autonomous mobile robots build user-specified structures from square building blocks. The swarm approach is inspired by social insects, which build large, complex structures through the collective actions of many simple agents acting with no centralized control or preplanning. The artificial system I present shares many desirable features with these natural ones, such as considerable parallelism and robustness to component loss. Further, unlike insect colonies, it can build particular desired structures according to a high-level design.

Robots in this system act without explicit communication or cooperation, instead using the partially completed structure to coordinate their actions. This mechanism is analogous to that of stigmergy used by social insects, in which insects take actions that affect the environment, and the environmental state influences further actions. I introduce a framework of "extended stigmergy" in which building blocks are allowed to store, process or communicate information. Increasing the capabilities of the building material (rather than of the robots) in this way increases the local availability of nonlocal structure information. Benefits include significant improvements in construction speed and in ability to take advantage of the parallelism of the swarm.

I describe system design and control rules for decentralized teams of robots that collectively build arbitrary solid structures in two dimensions. I present a hardware prototype, and discuss extensions to more general structures, including those built with multiple block types and in three dimensions.
Host: Justin Werfel, CSAIL, MIT