Sufficient and necessary conditions for absolute stability of time-delayed Lurie control systems ✩

In this paper, we present some sufficient and necessary conditions for the absolute stability of timedelayed Lurie control systems, which improve the results we obtained before for the absolute stability of direct control, indirect control and critical control of Lurie systems.We also derived certain simple and easy applicable algebraic sufficient conditions for the absolute stability of time-delayed Lurie control systems, which provide a convenient tool for practical control engineers in designing absolutely stable systems or stabilizing nonlinear control systems. © 2005 Elsevier Inc. All rights reserved.