Presented in this paper is a robust control scheme for
controlling systems with time delays. The scheme is based on the Smith
controller and the LQG/LTR (Linear Quadratic Gaussian/Loop Transfer
Recovery) methodology. The methodology is applicable to undenvater
vehicle systems that exhibit time delays, including tethered vehicles
that are positioned through the movements of a surface ship and
autonomous vehicles that are controlled through an acoustic link. An
example, using full-scale data from the Woods Hole Oceanographic
Institution’s tethered vehicle ARGO, demonstrates the developments
