Output tracking of stochastic nonlinear systems with unstable linearization

This paper studies the output tracking problem for a class of stochastic nonlinear systems whose linearization parts may have unstable modes via output-feedback control. This is in contrast with most of the existing results where only state-feedback control is considered. On the basis of the homogeneous domination technique, an output tracking controller is designed. It is shown that the expectation of tracking error can be made arbitrarily small while all the states of the closed-loop system remain to be bounded in probability. Finally, a simulation example is given to illustrate the effectiveness of the tracking controller.