Robust Feedback Control for Nonlinear Systems with Uncertain Input Dynamics and Unknown Control Direction

Abstract

In this paper, the robust feedback control problem is investigated for a class of nonlinear systems with uncertain input dynamics and unknown control direction. The uncertainty is restricted to be minimum-phase. First, by constructing a positive definite function guaranteeing the Barbalat's condition, a robust adaptive stabilizing controller is derived for the system unforced by disturbance. Then, a robust adaptive control law is designed for the system forced by disturbance such that the closed-loop system is convergent and the robust L₂-gain from disturbance to penalty signal is less than a given level.