Preliminary Design and Testing of a Resetting Combination Anchor, Antenna, and Tether Mechanism for a Spherical Autonomous Underwater Vehicle

Abstract

This article details the preliminary design and testing of a Resetting Anchor/Antenna Tether Mechanism (RAATM) for an autonomous underwater vehicle (AUV). The proposed mechanism is intended to enable an AUV to secure itself to the seabed, ascend, descend, transmit and receive signals via the tether, retract the anchor, and re-anchor again as required. The ability of an AUV to passively loiter on station for extended periods preserves power and may otherwise expand mission capabilities for a variety of underwater vehicles. If they are capable of communication through electromagnetic transmission, AUVs equipped with such technology may be utilized to form mobile networks that may, in turn, receive external communications from above the surface. Spherical AUV (SAUV) capabilities may be especially enhanced through the integration of the proposed mechanism. The RAATM was designed for integration with the Wreck Interior Exploration Vehicle (WIEVLE), a small SAUV designed for operations in entanglement-prone, extreme environments, but the RAATM may be used in any suitably-sized underwater vehicle capable of safely contacting the ocean floor. A prototype of the anchoring portion of the mechanism was constructed, and anchoring strength was tested repeatedly in three types of sediment, under varied configurations and loading angles, with promising results.