Page 12: of Maritime Reporter Magazine (April 2022)

The Path to Zero

A Clear Path to Lower Emissions through Autonomous Robotics t’s not a stretch to say that the underwater body of a ship is vances the hardware and delivers the capability to the marine the most important of all the myriad systems that make up industry through Robot-as-a-Service.

a ship. Yet, it’s often near the bottom in terms of routine Through a Small Business Technology Transfer Program

Imaintenance and monitoring. The hull receives a visual (STTR) with the Offce of Naval Research, Greensea Systems inspection once or twice a year and a more thorough inspec- set out to develop a means of establishing position and navi- tion in dry dock every 5 years (or so). Its allowed to get fouled, gating on a ship’s hull without the use of external sensors or reducing its hydrodynamic performance and the methods em- preloaded drawings of the ship. Over the past 4 years, Green- ployed to remove the fouling can shorten the life of the protec- sea leveraged OPENSEA, its open architecture platform for tive coating. This is in stark contrast to how other systems, marine robotics, to serve as the backbone of a novel position- like the propulsion engines, on board are managed in terms of ing and navigation system.

inspection and maintenance. Recognizing the need for a custom hardware solution,

Why is this? Simply put, underwater maintenance falls into Greensea designed a crawler assembly to integrate with the the nebulous “too hard” bucket. Being underwater, it’s out of commercially available Videoray MSS Defender ROV to cre- sight (out of mind?) and unless something catastrophic hap- ate a vehicle capable of fying into position alongside a ship, pens, its condition is “good enough.” Inspections need to be then inverting itself and attaching to the hull to commence on completed by divers or robots, both of which are expensive and hull activities. The crawler was designed specifcally to sup- include varying degrees of complexity, risk and interruption to port on-hull navigation, incorporating precision track encoders the ship’s routine. The result is these evolutions typically only for odometry and velocimetry, a fber optic gyrocompass for get completed when dictated by external factors, such as regu- heading and orientation, a Doppler Velocity Logger for relative latory requirements or (potential) severe performance degrada- motion tracking, and tracks specifcally optimized for use on tion of the hull. In other words, it is reactive maintenance. approved U.S. Navy coating systems. A low pressure vortex

Armach Robotics is setting out to change the paradigm generator provides the necessary adhesion to the hull without and turn underwater maintenance into a proactive endeavor the use of magnets. Built on OPENSEA, Greensea’s EOD through the use of small autonomous robots. This will be the Workspace was easily modifed to incorporate crawler control, frst in a series of three articles discussing Armach’s approach enabling manual piloted operation of the robot on a ship’s hull. and vision for proactive hull maintenance, and will provide an With the concept proven, Armach Robotics will continue to overview of the technical approach being taken for the robot, evolve the hardware design to improve operation.

with follow-on articles delving into proactive in-water clean- To establish navigation capability, the robot creates a new ing (aka grooming) and the concept of hull intelligence. coordinate system, transforming the ship’s hull into a 2-D

First a bit of background and introduction. Greensea Sys- plane. With the new coordinate plane established, odometry tems, creator of OPENSEA, spun Armach Robotics off in the and heading data can provide basic navigation capability, but fall of 2021 to be the exclusive provider of its recently de- ultimately this is simple dead reckoning, and error can easily veloped “hullographic” (meaning hull relative) navigation and grow to an unacceptable level. To combat the error growth, the autonomy technology for ship maintenance and inspection. features of the hull can be used as reference points much like

Greensea will continue to advance the software as Armach ad- water towers, steeples or points of land on a nautical chart. For 12 Maritime Reporter & Engineering News • April 2022