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

New results on adaptive tracking by output feedback for a class of uncertain nonlinear systems

研究了一类不确定非线性系统的自适应输出反馈实际跟踪控制问题.解决该控制问题的困难主要源于此类系统控制系数不确定,并具有依赖于不可测状态的增长且其增速是关于输出的多项式函数.首先,通过推广现有的K-滤波器,引入了新的动态高增益K-滤波器,并基于此构造了状态观测器.然后,应用反推技术,成功的设计了系统的自适应输出反馈跟踪控制器.主要结果表明,通过设计参数的适当选择,所构造的控制器能保证闭环系统的所有状态全局有界,并且当时间足够大时,跟踪误差收敛到零点的既定小邻域内.

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.