Robust output feedback control for a class of time-varying systems

In this paper, we study the robust output feedback control for a class of time-varying systems where the observer is used to estimate the system states and a learning scheme is also proposed to learn the time-varying parameters. A regulator control problem is pursued with known time-varying bounds. It is shown that to estimate the system states asymptotically only part of the time-varying function need to be learned, not necessarily all the time-varying parameters. The designed output feedback closed-loop control system guarantees a robust norm bound performance measure and uniformly asymptotic stability based on quadratic stability.