Adaptive control of a class of nonlinear systems by output feedback

This paper studies the global states regulation problem via output feedback for a class of uncertain nonlinear systems and a class of their cascade systems. The uncertain nonlinear perturbed terms of the considered systems are assumed to satisfy a generalized condition which is related to an unknown constant and is more relaxed than the existing triangular-type condition. Due to the presence of unknown parametric uncertainty, a dynamic output compensator with dynamically updated gains is explicitly constructed based on nonseparation principle. It is proved that the compensator can globally regulate all the states of the uncertain nonlinear system to zero while maintaining the globally bounded stability of the closed-loop system. An example illustrates the effect of our result.