New results on adaptive tracking by output feedback for a class of uncertain nonlinear systems
一类不确定非线性系统自适应输出反馈跟踪控制的新结果

We consider the adaptive practical tracking control by output feedback for a class of uncertain nonlinear systems. This class of systems has an uncertain control coefficient and unmeasured states dependent growth with growth rate of polynomial-of-output. To deal with the difficulty caused by this control coefficient, we extend the existing K-filters to new dynamic K-filters with high gains; based on which we construct a state observer. Then, the adaptive tracking controller by output feedback is successfully designed using the backstepping technique. It is shown that if the design parameters are suitably chosen, the designed controller guarantees the closed-loop system states to be globally bounded, and the tracking error to converge to the prescribed small neighborhood of the origin after the elapse of a long time.