The US Navy is developing ways to recharge underwater unmanned vehicles (UUVs) using undersea wireless technology.
The Navy uses UUVs for many types of missions, including the location and identification of underwater threats such as mines, ocean floor mapping, and optimizing remote sensing platforms. The ability to use wireless technology to charge UUV batteries while underwater may significantly decrease time between missions, improving overall utility.
"Underwater data and energy transfer are expected to multiply the effectiveness of Navy-operated UUVs and other unmanned platforms by providing a vehicle-agnostic method for autonomous underwater energy charging," said Alex Askari, Naval Surface Warfare Center, Carderock Division (NSWCCD) technical lead. This technology can be used on many different types of vehicles.
NSWCCD supported Naval Undersea Warfare Center, Division Newport (NUWC DIVNPT) in demonstrating this capability during the first-ever Naval Technology Exercise (ANTX), Aug. 10-14 at the Stillwater Basin Test facility in Newport, Rhode Island. ANTX is a weeklong showcase of Undersea Constellation technology from NUWC DIVNPT, and Space and Naval Warfare Systems Command SPAWAR Systems Center Pacific (SSC PAC).
NSWCCD previously executed a successful underwater wireless energy transfer demonstration in a 6,000 gallon tank at its West Bethesda, Maryland facility, June 29-July 3.
These concepts of wireless underwater energy transfer, such as Forward Deployed Energy and Forward Deployed Energy and Communications Outpost (FDECO), were born in NSWCCD's Disruptive Technologies Lab.
"We want to recharge a battery underwater through wireless technology, and we want to know the batteries charge to the highest fidelity," Mayer Nelson, NSWCCD technical project manager said. The NSWCCD demonstration was a collaborative effort as Carderock hosted teams from NUWC DIVNPT and SSC PAC.
"The NUWC team was on-hand to simulate the full capabilities of the NUWC-developed Mid-sized Autonomous Research Vehicle (MARV) UUV, as well as to provide assistance with testing," Joseph Curran, NSWCCD integration lead said.
The MARV is 16.5 feet long and just slightly more than one foot in diameter for testing different UUV programs and technologies.
Carderock Division's developed technology enables power transmission between underwater systems, such as UUVs. During the main demonstration on July 3, the team was successful in transferring power wirelessly from an underwater docking station to a MARV UUV section, and ultimately to the UUV's battery, which was charged at 2 kilowatts while submerged, according to Nelson.
A battery State of Charge (SOC) program developed by Dr. Michael Knauff, a Naval Ship Systems Engineering Station (NAVSSES) in Philadelphia electrical engineer was integrated by Crystal Lutkenhouse, a NSWCCD mechanical engineer.
"We tested a Carderock-developed algorithm and pulled in data from the actual battery; then ran voltage, current and temperature data through the data acquisition system," Knauff said.
During underwater energy transfer, this program was run using data that had been transferred wirelessly underwater using SSC PAC's underwater optical communications system and allowed an enhanced estimation of the charge on the battery through the SOC program.