Title :
On quantifying tolerable closed-loop uncertainty in frequency domain
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Melbourne, Parkville, VIC, Australia
Abstract :
Given a linear plant and a feedback controller it is natural to ask: How much uncertainty can be tolerated by the closed-loop while achieving a specified level of performance? In this paper, a characterization of this question is formulated in terms of a constrained optimization problem; the cost reflects the size of non-constant weights used to quantify system uncertainty across frequency and the constraint is a structured singular value characterization of the required level of robust performance. In the case of unstructured uncertainty the problem can be solved via a family of problems that are convex pointwise in frequency. An iterative algorithm is developed for the case of structured uncertainty.
Keywords :
closed loop systems; feedback; frequency-domain analysis; iterative methods; optimisation; robust control; singular value decomposition; uncertain systems; constrained optimization problem; convex pointwise problems; feedback controller; frequency domain quantification; iterative algorithm; linear plant; nonconstant weights; robust performance level; structured singular value characterization; system uncertainty quantification; tolerable closed-loop uncertainty quantification; unstructured uncertainty; Iterative methods; Optimization; Periodic structures; Robustness; Standards; Transfer functions; Uncertainty;
Conference_Titel :
Control Conference (ECC), 2013 European
Conference_Location :
Zurich
