Unmanned aerial vehicles (UAVs) and their sensors track and monitor wildlife, livestock, infrastructure, weather and construction progress, among other tasks.
Now, Naval Surface Warfare Center, Port Hueneme Division scientists and a local company want to use them to track corrosion or degradation on combat systems aboard Navy ships.
NSWC PHD and Aerial Alchemy, a remote-sensing technology company in Thousand Oaks, California, are partnering under a Cooperative Research and Development Agreement (CRADA) to solve how corrosion affects the performance of Navy ships’ combat systems and to find a way to detect corrosion remotely.
Aerial Alchemy develops medium and heavy-lift UAVs that use sensors equipped with lidar scanning and other imaging technology to accurately capture data used to generate a 3D digital representation of a physical asset, also known as a digital twin.
The partnership’s goal is to explore using the company’s drones and its processing system and visual data to detect areas that may have corrosion. As a drone flies over a specified area of a ship, such as a hull or the rear, it transmits video to create a digital model of a ship that contributes to the ship’s detailed analysis, including potential areas of concern for corrosion or rust.
Should the UAV and sensors detect corrosion, it will help give scientists an early head’s up of the issue, according to Alan Jaeger, NSWC PHD Office of Research and Technology Applications manager.
“The idea of the CRADA we are doing now is whether we can use various sensors to identify that information without having to put human eyeballs on it,” Jaeger said. “If we can, then the next step is putting that on drones or unmanned aircraft, so we don’t have to send a sailor on a ship; we can send a drone, and it can scan equipment and identify corrosion or undersurface damage, for example. If we can get that data, then we can start pre-planning for maintenance, preventative maintenance and repair operations.”
This is Aerial Alchemy’s second CRADA with NSWC PHD. The first CRADA focused on proving the stability, reliability and accuracy of the company’s UAVs in a maritime environment to successfully create an “as-built” digital model of USS Independence (LCS 2), which is used as a baseline digital twin. A digital twin is an intelligent digital representation of an analog asset or a 3D model, according to Chuck Spaulding, founder, and chief executive officer of Aerial Alchemy.
“We began working with the Navy in 2016 when everyone was trying to figure out what civil UAVs were and what they meant to them,” Spaulding explained. “The Navy was interested in exploring the usefulness of drones for remote sensing and remote inspections of combat systems on surface ships, which led to the first CRADA in 2018, and through that collaboration, we were able to create an exterior 3D as-built model of a ship at sea.”
With the second CRADA, the team can build on the successful results of the first CRADA and continue to improve precision navigation techniques while focusing on combining data from a thermal red, blue and green sensor that a visible camera uses, as well as multispectral, hyperspectral and tuning sensor wavelengths so they can be used to remotely detect and identify the chemicals generated during the corrosion process.
“By themselves, the data from each of these sensors do not provide sufficient information for the specific identification and automatic evaluation of the corrosion state of an asset,” Spaulding said. “However, when combined with a stable platform with precision navigation such as lidar and synthetic vision to align the ‘blended’ sensor data and advanced computational approaches involving machine learning and artificial intelligence algorithms in a digital twin, this solution should provide a more objective rating of surface deterioration much more efficiently, cost-effectively and safer than a human inspector could.”
The teams anticipate the drone-sensor technology Aerial Alchemy and NSWC PHD are working on will bring many benefits to the Navy and the warfighter, including reducing the labor costs of inspections and the ability to inspect difficult and high-risk areas. That advanced and early detection, in particular, would give the Navy a leg-up in treating corrosion, said Zachary Stephens, a materials engineer also with NSWC PHD.
“Because a lot of corrosion happens under the painted surface, you see it when it breaks through the painted surface, or you start to see physical flaws; and at that point, it’s almost too late to do touch-up work, so the early detection will be very valuable for planning maintenance actions and for knowing which system needs the maintenance and which ones don’t, as well as moving onto our condition-based maintenance model rather than our preventative based maintenance model,” Stephens explained.
Armen Kvryan, NSWC PHD lead materials engineer, has a doctorate in materials science and an extensive background on corrosion issues affecting combat systems from working in industry and academia. Kvryan, Jaeger and Stephens along with Aerial Alchemy partner, SAAZ Micro, Inc., an advanced imaging technology company in Simi Valley, California, are first conducting tests of the sensors in a laboratory to explore the different types of corrosion and degradation the sensors can identify on different kinds of metals, such as aluminum and steel.
“Our initial research will be on what sensors to use to detect corrosion and then figure out what sensors we can use and what materials we can detect corrosion or degradation on, because composites are not metal, so they don’t corrode,” Stephens said. “Although it would be ideal to have a (single) sensor that can detect all kinds of corrosion and degradation on the ship when you have composite versus aluminum or steel, they all have different signs and methods. One method may work on one type system but won’t work on another; the success of this test will determine where to focus our efforts.”