Global output feedback stabilization of upper-triangular nonlinear time-delay systems

In this paper, the problem of global output feedback stabilization for a class of upper-triangular nonlinear systems with time-varying time-delay in the state is considered. The uncertain nonlinearities are assumed to be higher-order in the unmeasurable states. Based on the extended homogeneous domination approach, using a low gain observer in combination with controller, the delay-independent output feedback controller makes closed-loop system globally asymptotically stable under a homogeneous growth condition.