Performance Evaluation of Composite Interval Systems

摘要

Interval model plays an important role in parametric robust control. This paper deals with the strict positive realness of a class of composite interval systems, and establishes a strong Kharitonov-like extreme point criterion. We also discuss the robust strict positive realness of the shifted interval plant-controller family, and improve some previous results in literature. Finally, for the collection of Popov plots of interval transfer function family, we prove that a large portion of its outerboundary comes from the sixteen Kharitonov transfer functions.