Avoidance of underwater cliffs for autonomous underwater vehicles

This paper introduces a method aiming to allow underactuated autonomous underwater vehicles navigating in an unknown environment to avoid underwater cliffs. Three electro-acoustic transducers situated in the front part of the vehicle provide bathymetric data. In this article we detail the method adapted to an irregular seabed, i.e., with substantial changes in depth like underwater cliffs. The obtained trajectories respect the dynamic constraints of the vehicle. We also explain how to choose the orientation angle of transducers in order to optimize the quality of seabed following. Our method was validated with the hydrodynamic simulator of the "Taipan" vehicle, which is our laboratory\´s autonomous underwater vehicle prototype.