Further input-to-state stability subtleties for discrete-time systems

This paper considers input-to-state stability (ISS) analysis of discrete-time systems using continuous Lyapunov functions. The contributions are as follows. Firstly, the existence of a continuous Lyapunov function is related to inherent input-to-state stability on compact sets with respect to both inner and outer perturbations. If the Lyapunov function is K_∞-continuous, this result applies to unbounded sets as well. Secondly, continuous control Lyapunov functions are employed to construct input-to-state stabilizing control laws for discrete-time systems subject to bounded perturbations. The goal is to design a receding horizon control scheme that allows the optimization of the ISS gain along a closed-loop trajectory.