Characterizing the critical parameters for docking unmanned underwater vehicles

Abstract

Docking an autonomous underwater vehicle (AUV) is a critical part of many current and envisioned Navy, commercial, and scientific missions. Many missions require an AUV to dock with a subsea node that is not restrained through attachment to the seafloor or to a surface platform significantly larger than the system that is docking into it. Space and Naval Warfare Systems Center Pacific (SSC Pacific) recently performed a series of tests to characterize the docking process of an autonomous underwater vehicle (AUV) with a suspended dock. Two methods of docking were performed: a “soft” optical dock where the vehicle tracked and followed a suspended light emitting diode (LED) beacon and a “hard” physical dock where the vehicle entered a docking structure. This docking testing will provide design support information for future undersea systems. A REMUS 600 with a hover-capable thruster package was the base test platform. It was outfitted with a directional acoustic transducer (DAT) for acoustic AUV-Dock-relative navigation and an optical quadrant detector for terminal approach and homing. A basic dock structure was constructed of PVC pipe, and instrumented with both acoustic and optical homing devices. Testing was performed at the SSC Pacific Transducer Evaluation Center (TRANSDEC) test facility. Key docking parameters evaluated during the testing included sensor update rates, vehicle kinematics, and dock inertial characteristics. SSC Pacific performed over 217 trials, with 105 successful hard and soft docks. There were 30 successful docks in 31 trials in the final hard dock series.