L_∞ dynamic surface control for a class of nonlinear pure-feedback systems with finite-time extended state observer

This paper presents a novel dynamic surface control (DSC) design for a class of nonlinear pure-feedback system without using adaptive approach. By introducing a set of alternative state variables and the corresponding transform, state-feedback control of the pure-feedback can be viewed as output-feedback control of a canonical system. To estimate unknown states of the newly derived canonical system and the lumped overall uncertainty, a finite-time extended state observer (ESO) is adopted. The closed-loop stability and convergence of the tracking error to a small compact set around zero are proved. Comparative simulations are included to verify the reliability and effectiveness of the proposed approach.