Adaptive output-feedback stabilization for a class of uncertain nonlinear systems

This paper investigates the problem of global adaptive stabilization by output-feedback for a class of nonlinear systems with uncertain control coefficients and unknown growth rate. By extending the classical K-filters, we introduce novel high-gain K-filters with a dynamic gain updated on-line inspired by [1, 2], and thus propose an observer to reconstruct the system state. Then, motivated by the universal control method in [3], the backstepping design approach is developed for the adaptive output- feedback stabilizing controller. It is shown that the global stability of the closed-loop system can be guaranteed by the appropriate choice of the design parameters.