September 23, 2011, Webb 1100

In this talk, I will describe new results on the design of norm-optimal controllers, subject to sparsity constraints. In particular, I will focus on the idea of re-writing the plant using block-diagonal factorizations to obtain the first algebraic characterization of stabilizability in terms of the sparsity pattern imposed on the controller. In addition, I will discuss how this factorization can be used to construct a convex parametrization of stabilizing controllers that satisfy the sparsity constraint and, in contrast to previous approaches, does not require an initial stabilizing sparsity-constrained controller. This work constitutes an extension of the Youla parameterization for the case of norm-optimal controllers subject to quadratically-invariant sparsity constraints (as defined by Rotkowitz and Lall). (This is joint work with Serban Sabau (UMD)).

Nuno C. Martins received the MS. degree in electrical engineering from I.S.T., Portugal, in 1997, and the Ph.D. degree in Electrical Engineering and Computer Science with a minor in Mathematics from Massachusetts Institute of Technology (MIT), Cambridge, in 2004. He has also concluded a Financial Technology Option program at Sloan School of Management (MIT) in 2004. He is currently Assistant Professor at the Department of Electrical and Computer Engineering, University of Maryland, College Park, where he is also affiliated with the Institute for Systems Research and the Center for Applied Electromagnetics. He received a National Science Foundation CAREER award in 2007, the 2006 American Automatic Control Council O. Hugo Schuck Award, the 2010 Outstanding ISR Faculty award and the IEEE CSS George Axelby Award in 2010. He is also a member of the editorial board of Systems and Control Letters (Elsevier) and of the IEEE Control Systems Society Conference Editorial Board.