INVITED PRESENTER III

Bassam Bamieh's research is centered around notions of uncertainty and robustness in control and dynamical systems. These notions are applied to the study of distributed systems and their control. These include the design of distributed localized controllers for large scale systems, and analysis of the role of uncertainty in shear flow turbulence and transition. His group carries out several research activities including Atomic Force Microscopy, design and control of multi-micro cantilevers, optical actuation via optical tweezers, and control and analysis of turbulent shear flows. He is an Associate Professor of Mechanical Engineering at the University of California at Santa Barbara, which he joined in 1998. Previously, he was with the department of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign, which he joined after receiving the PhD from Rice University in 1991. Professor Bamieh is a member of IEEE, ASME, SIAM and the APS. He is a past recipient of the AACC Hugo Schuck best paper award and an NSF CAREER award. http://www.engineering.ucsb.edu/~bamieh

INVITED PRESENTATION III: Distributed Systems and Distributed Control

Spatially distributed systems have attracted much recent attention in which the focus has been on the architectural issues involved in the design of large spatially distributed arrays of sensors and actuators. Such large scale systems have become technologically feasible with the advent of MEMS technology where potentially thousands or tens of thousands of actuators and sensors must act in a coordinated manner to achieve globally defined objectives. In these new problems, effective control oriented modeling of such complex spatially distributed phenomena has also become a significant issue. In some of these areas, the current limits are imposed by our modeling and understanding of the control problem rather than by device technology.

In this talk we will summarize two current research directions in distributed systems. The first is the architecture of distributed controllers in large distributed arrays, and the second is the modeling of the complex spatially distributed phenomenon of fluid flow turbulence. The common link between these two problems is distributed systems theory. The central issue in distributed coordinated control of large arrays is the communication requirements between sensors and actuators and how far local information needs to be passed to achieve certain levels of performance. We will summarize recent research in this area, which uses tools similar to those used in multi-dimensional systems theory. An example of distributed control of capacitively actuated micro-cantilevers will be used to illustrate these concepts.

The recent interest in fluid flow control has stimulated interaction between fluid dynamics and control theory. We will summarize recent research, which indicates that the tools of uncertainty and robustness analysis can be used to obtain very parsimonious

models of shear flow turbulence. There are fascinating links between this theory and robust control theory. It turns out that in high shear flows, the Navier-Stokes equations are a dynamical system that is extremely sensitive to external forcing and dynamical perturbations. This has lead to a new way of looking at hydrodynamic instabilities in shear flow problems, and to new insights into how to control such flow phenomena.