H∞ almost disturbance decoupling with stability for uncertain nonlinear systems

This paper deals with an almost disturbance decoupling issue for uncertain single-input single-output nonlinear control systems. The class of systems we consider has a weak triangular structure. Its unobserved subsystem is assumed to have a finite L
2
-gain in some sense. By making use of the backstepping technique, some sufficient conditions are given to solve the H
∞
almost disturbance decoupling problem with global asymptotic stability by full-state feedback or partial-state feedback. Our results extend several existing results.