Output feedback backstepping control for non-linear systems using an adaptive finite time sliding mode observer

In this paper, a class of non-linear systems in normal form is considered, which is composed of internal and external dynamics. An adaptive finite time sliding mode observer is first designed so that the system states, unmatched uncertain parameters and matched uncertainties can all be observed in finite time. Then, the systematic backstepping design procedure is employed to develop a novel output feedback backstepping control (OFBC). The proposed OFBC method can stabilize the considered non-linear systems despite the presence of non-linear internal dynamics and unmatched uncertainties. A Lyapunov method is used to ensure that the closed-loop system is asymptotically stable. Two MATLAB simulation examples are used to demonstrate the method.