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 Title: Robustness in Feedback Systems (Frequency Domain) Author(s): Ting, Thomas Leo Department / Program: Electrical Engineering Discipline: Electrical Engineering Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Engineering, Electronics and Electrical Abstract: The research in this dissertation is motivated by the basic question "What can and cannot be accomplished by feedback control?" In particular, this dissertation shall address three basic issues: (a) Determining which types of controllers are optimal for certain classes of control problems, (b) Investigating the absolute limitations of feedback control for multiobjective problems and the performance tradeoffs available between the various objectives, and (c) Developing efficient methods for synthesizing robustly stabilizing controllers for families of plants featuring block-structured uncertainty.With regard to the issues identified above, the principal contributions of this dissertation can be outlined as follows. First, it is shown that for the problem of robustly stabilizing a family of plants featuring dynamic uncertainty, linear time-invariant controllers perform as well as arbitrary nonlinear time-varying controllers. Second, a new controller synthesis procedure called residue iteration is developed for synthesizing robustly stabilizing controllers for families of plants featuring block-structured uncertainty. This method is simpler and numerically more attractive than any previously existing technique. Finally, an algorithm is presented which enables one to compute an absolute upper bound on the performance levels attainable in multiobjective H$\sb\infty$-optimization problems. Issue Date: 1987 Type: Text Description: 103 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987. URI: http://hdl.handle.net/2142/69366 Other Identifier(s): (UMI)AAI8721770 Date Available in IDEALS: 2014-12-15 Date Deposited: 1987
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