Asymptotic tracking of a reference state for systems with a feedforward structure

We consider the problem of asymptotic tracking for a system which can be wr itten in a feedforward form. The data of a bounded reference state trajecto ry is assumed. Our solution relies on a Lyapunov construction. The time-var ying state feedbacks obtained are bounded and ensure the global uniform asy mptotic stability when the signals are periodic and the local exponential s tability of the reference state trajectory of the closed-loop system. (C) 1 999 Elsevier Science Ltd. All rights reserved.