Output feedback stabilization of stochastic nonlinear systems with unknown output function

This paper studies the problem of output feedback stabilization for a class of stochastic nonlinear systems with the unknown output function. For stochastic nonlinear systems, the maximal open sector Delta of output function is given. As long as output function belongs to any closed sector included in Delta, by constructing a reduced-order observer and C-2 Lyapunov function and using the homogeneous domination method, an output feedback controller is constructed to render the closed-loop system globally stable in probability and all states can be regulated to the origin almost surely.