October 14, 2016, Lucy Pao, University of Colorado Boulder

Friday, October 14, 2016, 3pm-4pm
8 St. Mary’s Street, PHO 210
Refreshments at 2:45pm

Lucy Pao
University of Colorado Boulder
CISE Resident Scholar

Control of Atomic Force Microscopes to Achieve Faster Imaging

An atomic force microscope (AFM) can provide images with resolution at the atomic scale, and AFMs have been instrumental in enabling the understanding of systems with nanometer-scale features. However, the time required to attain a quality AFM image is typically on the order of several minutes, and substantial motivation exists to reduce the imaging time in AFMs. In this talk, we will first overview selected recent research in improving AFM imaging speeds. We will then discuss an on-going collaboration with Professor Sean Andersson’s group at BU in working to achieve high-speed atomic force microscopy through compressed sensing. With compressed sensing, only a small number (as low as 10%) of the pixels in an image need to be sampled to generate an accurate image. Sampling at a fraction of the pixels also reduces the interactions between the AFM tip and the sample surface, leading to improved integrity of both the sample and the AFM tip. Minimizing the imaging time in this scheme requires that the rest-to-rest maneuver times between point measurements be minimized. We will discuss our recent work in developing and proving stability of a near time-optimal controller for a simple model of an AFM stage, and we will also overview on-going work to develop controllers to address more complete dynamics of AFM systems. We shall close by discussing other applications for the control methods developed and future directions for our collaborative work with the Andersson group.

Lucy Pao is currently Professor in the Electrical, Computer, and Energy Engineering Department and Professor (by courtesy) in the Aerospace Engineering Sciences Department at the University of Colorado Boulder. She earned B.S., M.S., and Ph.D. degrees in Electrical Engineering from Stanford University. Her research has primarily been in the control systems area, with applications ranging from atomic force microscopy to disk drives to digital tape drives to megawatt wind turbines and wind farms. Earlier major awards received include a National Science Foundation (NSF) Early Faculty CAREER Award, an Office of Naval Research (ONR) Young Investigator Award, and an International Federation of Automatic Control (IFAC) World Congress Young Author Prize. Selected recent honors include elevation to IEEE Fellow in 2012, the 2012 IEEE Control Systems Magazine Outstanding Paper Award (with K. Johnson), election to Fellow of IFAC in 2013, and the 2015 SIAM J. Control and Optimization Best Paper Prize (with J. Marden and H. P. Young). Selected recent and current professional society activities include being General Chair for the 2013 American Control Conference, an IEEE Control Systems Society (CSS) Distinguished Lecturer (2008-2014), a member of the IEEE CSS Board of Governors (2011-2013 (elected) and 2015 (appointed)), Fellow of the Renewable and Sustainable Energy Institute (2009-present), IEEE CSS Fellow Nominations Chair (2016- ), member of the IFAC Fellow Selection Committee (2014-2017), and member of the International Program Committees for the 2016 Indian Control Conference, the 2016 IFAC Symposium on Mechatronic Systems, and the 2017 IFAC World Congress.

Faculty Host: Sean Andersson
Student Host: Yue Zhang