Minimal-order observer and output-feedback stabilization control design of stochastic nonlinear systems

A minimal-order observer and output-feedback stabilization control are given for single-input multi-output stochastic nonlinear systems with unobservable states, un- modelled dynamics and stochastic disturbances. Based on the observer designed, the estimates of all observable states of the system are given, and the convergence of the es- timation errors are analyzed. In addition, by using the integrator backstepping approach, an output-feedback stabilization control is constructively designed, and sufficient condi- tions are obtained under which the closed-loop system is asymptotically stable in the large or bounded in probability, respectively.