The USC Center for Robotics and Embedded Systems has posted a dissertation by Chris Jones titled, A Principled Design Methodology for Minimalist Multi-Robot System Controllers (PDF format). The 121 page document describes the design of a general purpose control system for multiple robots. Previous demonstrations of multi-robot control systems have tended to focus on specific tasks rather than general purpose multi-robot control. While at USC, Jones did a lot of research on multi-robot control and has written a number of other papers on the subject.