A Robust System for Deploying Various External Payloads from Cylindrical UUVs

ARMADA Marine Robotics is partnering with Woods Hole Oceanographic Institution (WHOI) to address the Navy need for external payload deployment systems for cylindrical Unmanned Underwater Vehicles (UUVs). WHOI has previously developed and demonstrated both internal and external payload deployment systems for 7.5-inch and 12.75-inch UUVs, so our proposed approach is already partially validated. They invented a patented technique that uses a vacuum force in a cavity, sized to compensate for the negative buoyancy of the payload, such that the vehicle sees no net change in buoyancy when either transporting or post-delivery of the payload. The approach also uses native acoustics on the vehicle for commanding the release of the payload as well as to check the status of the payload for status such as battery health or leak detection so that no through-hull modifications are required. This prior work significantly de-risks our proposed solution, so that our Phase I effort can focus on the main technical challenge of how an external payload deployment system will modify the hydrodynamic behavior of the host UUV and affect its controllability and maneuverability. We will design and fabricate several "dummy" payloads that are sized to serve as surrogates for likely payload dimensions. Candidate diameters are 2.5 inches, matching WHOI's miniature DSP board to create small transponders, and 4.875 inches, matching the A-size profile common to many aerial and surface deployed payloads. These dummy payloads will be attached to tabs on a strongback that is band clamped to the vehicle in the same way as an actual payload. This is a flexible attachment mechanism that allows us to quickly explore how the size, number, and position of multiple payloads affects the flight stability and endurance of a UUV. The enhanced energy monitoring capabilities of the new REMUS core electronics board will allow the relative drag contributions of both the payload and its mounting hardware to be quantified during in-water testing by analyzing vehicle state data after a series of test missions.  The Phase I Base will focus on the aforementioned in-water testing. The Phase I Option will focus on designing actual payloads that can be fabricated and deployed during testing in Phase II, as well as developing a Phase II plan to quantify payload drop accuracy. As part of the Option, we will also survey the trade space of native acoustics for target UUVs, as well as the trade space of acoustic modems and other available hardware that could be integrated into a deployable payload and used to communicate and trigger its release. This will maximize the applicability of the proposed approach to external payload deployment systems across a variety of UUV platforms.