Global Output-Feedback Stabilization for Nonlinear Systems with Polynomial Growth

This paper is concerned with the global adaptive stabilization via output feedback for a class of uncertain planar nonlinear systems in the presence of uncertainty in both state and output equations. The systems under consideration are assumed to be dominated by a bounding system which is linear growth in the unmeasurable states but can be a polynomial output-dependent growth with unknown growth rate. Motivated by the closely related works, we propose a non-identifier based output feedback control scheme by using the idea of universal control integrated with a linear high-gain observer, whose gains are composed of two components, and both of them are dynamically updated in the new forms. The designed controller can globally regulate the states of the original system while maintaining global boundedness of the closed-loop system.