  This paper deals with the exponential input-to-state stabilization with
respect to boundary disturbances of a class of diagonal infinite-dimensional
systems via delay boundary control. The considered input delays are uncertain
and time-varying. The proposed control strategy consists of a constant-delay
predictor feedback controller designed on a truncated finite-dimensional model
capturing the unstable modes of the original infinite-dimensional system. We
show that the resulting closed-loop system is exponentially input-to-state
stable with fading memory of both additive boundary input perturbations and
disturbances in the computation of the predictor feedback.
