Further Results on Global Asymptotic Regulation Control for a Class of Nonlinear Systems With iISS Inverse Dynamics

This note studies the global asymptotic regulation problem for a class of nonlinear systems with integral input-to-state stable (iISS) inverse dynamics by output feedback. It does not require a priori knowledge of the sign of the high-frequency gain. The considered system represents more general classes of nonlinear uncertain systems. The novelty of this note lies in the observer whose gain comes from a time-varying Riccati differential equation.