A Universal Control Approach for a Family of Uncertain Nonlinear Systems

We study the problem of global adaptive stabilization by output feedback for nonlinear systems with unknown parameters. The class of uncertain systems under consideration is assumed to be dominated by a bounding system which is linear growth in the unmeasurable states but can be a polynomial function of the system output, with unknown growth rate. To achieve global stabilization in the presence of parametric uncertainty, we propose a non-identifier based output feedback control law using the idea of universal control integrated with the linear-like output feedback control scheme proposed recently. In particular, we explicitly design a universal output feedback controller which globally regulates all the states of the uncertain system while maintaining global boundedness of the closed-loop system.