This talk describes ongoing work toward active manipulation of micro-scale mechanical and biological manufacturing processes. Such manipulation often requires the coordinated control of many agents (whether micro-robots or micro-organisms) using only a small number of control inputs. Two examples will be used to illustrate a conceptual framework for addressing this problem.

First, this talk considers the problem of controlling a group of agents under the constraint that every agent must be given the same control input. This problem is relevant for the control of mobile micro-robots that all receive the same power and control signals through an underlying substrate. Despite this restriction, results in simulation demonstrate that it is possible to get a group of micro-robots to perform useful tasks. All of these tasks are derived by thinking about the relationships between robots, rather than about their individual states.

Second, this talk considers the problem of controlling a large group of agents indirectly, by specifying the motion of a small group of moving targets. In particular, it considers the problem of maintaining a minimum separation distance between each pair of agents, something that it is impossible to do with only one target. Results in simulation support the conjecture that only two targets are necessary to maintain separation between any number of agents.

BIOGRAPHY

Dr. Bretl received a B.S. in Engineering and a B.A. in Mathematics from Swarthmore College in 1999. He received a M.S. in 2000, then a Ph.D. in 2005, both in Aeronautics and Astronautics from Stanford University, where he developed motion planning algorithms for legged robots. Since August 2006, he has been an Assistant Professor of Aerospace Engineering at the University of Illinois at Urbana- Champaign, where his work ranges from micro-manipulation to the design of neural interfaces.