Simple Adaptive Asymptotic Tracking Scheme for Parametric Strict-Feedback Nonlinear Systems with Additive Disturbance

Abstract

We consider the same class of systems in a previous paper, that is, a class of parametric strict-feedback nonlinear systems with additive disturbance. By using the backstepping technique, adaptive control algorithm is developed. Unlike the existing control schemes for systems with additive disturbance, no knowledge is assumed on two times continuous differentiability of the disturbance. Also, the developed backstepping controller does not require the uncertain parameters to be restricted within a known interval. Furthermore, overestimation of the system parameters is removed by employing the tuning functions method. It is shown that the proposed controller guarantees not only the stability in the sense of Lyapunov definition, but also the asymptotic tracking.