Global output feedback control with disturbance attenuation for minimum-phase nonlinear systems

This paper deals with the problem of disturbance attenuation with stability for a class of minimum-phase nonlinear uncertain systems by output feedback. In contrast to the state-feedback case, a nonlinear, not necessarily linear L2, gain is employed to characterize the disturbance rejection level. A constructive output feedback design is described to achieve global asymptotic stability while the effect of the disturbance on the output is diminished to an arbitrary degree of accuracy. Sufficient conditions are additionally provided to yield a nonlinear output feedback solving the standard L2-gain disturbance attenuation problem with internal stability.