Robust output feedback control of time-delay nonlinear systems with dead-zone input and application to chemical reactor system

This paper investigates the problem of robust output feedback control for a class of time-delay nonlinear systems with unknown continuous time varying output function. Unlike the previous studies, the considered systems allow the presence of dead-zone nonlinearities, continuous disturbances and time-varying delays. A new robust control scheme is constructed by introducing coordinate transformations that draws the dead-zone characteristic as well as modifying a double-domination method cooperating with integral Lyapunov functions. A combined system is established to perform a one-step mechanism for constructing a continuous controller which guarantees that all closed-loop signals are ultimately uniform bounded. The proposed scheme is finally applied to a two-stage chemical reactor system with dead-zone input and external disturbances to illustrate the effectiveness and performances.