NSLS-II Seminar

If you would like to meet with these speakers after this presentation, please contact the host,enazaretski@bnl.gov prior to this presentation to coordinate a time slot.

This talk will focus on control systems theoretic analysis and synthesis of new modes of operations that significantly expand the range of performance specifications of nanopositioning systems. We will present a systems theory framework to study fundamental limitations on the performance of these devices. In particular, we will characterize the inherent fundamental trade-offs between resolution, tracking-bandwidth, and reliability specifications on positioning capability of these devices. In addition to determining fundamental limitations, this framework leads to a better understanding of existing technology and in overcoming some technological hurdles that were previously thought to be fundamentally limiting. The analysis is done in robust optimal-control setting with various architectural constraints that arise typically in nanopositioning systems imposed on both one- and two- degrees of freedom control-design frameworks. We show design strategies for improving some common existing nanopositioning systems, making nanopositioning systems insensitive to modeling uncertainties, and feedback designs that achieve simultaneously high bandwidth, resolution and robustness to modeling uncertainties. The outcomes of this research will be corroborated with experimental results on a nanopositioning system of an atomic force microscope. Experimental results that demonstrate significant improvements in bandwidth, resolution and robustness over common existing designs will be presented.