1994 Volume 7 Issue 7 Pages 255-264
Parametric absolute stability is considered for nonlinear feedback control systems consisting of a linear plant with uncertain parameters, a linear controller with tuning parameters, and a sectorial bounded nonlinearity. The stability concept originally defined for Lur'e systems, provides a mathematical framework for solving the joint problem of feasibility and stability of equilibrium states. The central issue of this problem is the change of the equilibrium state caused by the variations of reference inputs and parameters, which may affect stability. In this paper, the plant and controller are supposed to be stable or to possess one pole at the origin. Popov-type sufficient conditions are presented for parametric absolute stability.