COMPUTERS & ELECTRICAL ENGINEERING, cilt.30, ss.153-165, 2004 (SCI İndekslerine Giren Dergi)
In this paper, robust gain margin, robust phase margin and Nyquist envelope of interval systems are studied. It is first presented that the robust gain and phase margins of a control system with an interval plant family are achieved at one of the Kharitonov plant by using the interlacing theorem and virtual compensator concept. Then, using the generalized Hermite-Biehler theorem, it is shown that the outer boundary of the Nyquist envelope of a stable interval plant is covered by the Nyquist plots of the 16 Kharitonov plants family. Examples are given to illustrate the method presented. (C) 2003 Elsevier Ltd. All rights reserved.