External Payload Deployment System for Cylindrical UUVs

The Navy has identified a need for External Payload Deployment Systems (EPADS) for cylindrical Unmanned Underwater Vehicles (UUVs) between 5 and 21 inches in diameter. ARMADA Marine Robotics has assembled a team of experts to address this need with this Phase II SBIR. This effort will build upon our successful Phase I Base effort that determined an A-Size (4.875” diameter x 36”) payload body as a suitable form factor for delivering a 5kg module. Under Phase I work we validated hydrodynamic simulations with in-water testing to quantify the effects of multiple payloads and payload configurations on vehicle endurance and controllability. In-water tests were conducted with proprietary hydrodynamic A-Size dummy payloads carried on a REMUS 600 UUV. It was confirmed that two A-Size external payloads would not decrease the UUV mission time by more than 25% and the parasitic drag of the mounting hardware would be less than 10% over the unmodified vehicle drag.  EPADS is based on previous work at the Woods Hole Oceanographic Institution (WHOI) in deliverable transponders. The approach uses a payload that can be neutrally ballasted in a range of seawater densities, including freshwater, so that it has no effect on host UUV buoyancy when attached. Upon receiving an acoustic release command from the UUV, a motor opens a valve that floods a vacuum, making the payload negatively buoyant, and the payload detaches and descends to the seafloor target location. The UUV, which sees no net ballast change upon release of the payload and maintains neutral buoyancy throughout the deployment. WHOI has expressed interest in licensing and we will continue to partner with WHOI for development in Phase II. Work under the Phase II Base effort will include fabrication of the A-Size prototype designed in the Phase I Option, followed by bench, dockside, and tank validation testing. After a Critical Design Review, a revised design will be made and four units fabricated. Tank and open-water testing will be conducted to quantify deployment accuracy under, leveraging a REMUS 600 UUV as the host vehicle for the open-water tests. A Phase II Option is proposed that expands external payload deployment capabilities to other module sizes and classes of UUVs.