Nonlinear H∞ almost disturbance decoupling and adaptive stabilization without overparametrization

In this paper we study, incorporating previous results, the H_∞ almost disturbance decoupling and adaptive stabilization problem, for a class of systems affected simultaneously by time dependent disturbances and constant unknown parameters. We provide a unique control law which is not overparametrized, and not dependent on the unknown parameters of the system such that the time dependent disturbances are attenuated, in a sense formally stated in the literature, with an arbitrary degree of accuracy. Furthermore, the closed loop system, for time dependent disturbances identically zero and arbitrary constant unknown parameters, is globally asymptotically stable under regularity conditions