Observer-based backstepping control using online approximation

This paper extends the applications of neurocontrol approaches to a new class of nonlinear systems diffeomorphic to output feedback nonlinear systems with unmeasured states. A neural-based adaptive observer is introduced for state estimation as well as system identification using only output measurements during online operation. The controller is designed by using the backstepping control design procedure. Nonlinear damping terms are introduced to prevent the instability arising from the state estimation error. The stability analysis for the proposed approach is provided, and the feasibility is investigated by an illustrative example through a numerical simulation