Robust CLRF based nonlinear control design for time delay systems

The concept of control Lyapunov-Razumikhin function (CLRF) has been introduced as a tool for designing globally stabilizing control law for time delay systems. The control law has the same form as the domination redesign control law for nondelay systems which is (inverse) optimal and, hence, provides infinite gain margin and a nonlinear equivalent of 60/spl deg/ phase margin. In this paper we show that the CLRF based control laws also posses robustness to input unmodeled dynamics. The robustness to static input uncertainties is the same as the one of optimal nondelay systems. The robustness to dynamic uncertainties proven in this paper is weaker than that of optimal systems.