109 of transfer of invasive species,” he says. “We do this in a way that is friendly to hull coating systems and can be completed in ways that avoid disrupting ship schedules. “The idea of a crawler using lowpressure suction and rubber tracks to drive around on a surface, by itself, is not new to the industry,” he adds. “Other companies have done that with various small ROVs for inspecting inside large storage tanks, but the world of small marine robotics is constantly advancing, and we saw this specific need.” Greensea began developing the navigation and autonomy technology in 2018, building on earlier subsea robotics work and leading to a proof-of-concept phase with support from the US Navy. Armach was formed in late 2021 to deliver the service, with Carnival Cruise Lines becoming an early adopter and service development partner. Proof of concept For the proof-of-concept phase, Greensea’s early testing with existing systems proved unsatisfactory, Lander says, leading to the development of the HSR. Armach plans to improve it iteratively to increase efficiency and performance as the company learns more through operational experience and customer feedback. The teamworked onmore than a dozen vessels of various sizes during the HSR’s development, carrying out test cleanings in ports in NewEngland, Virginia, Florida and Texas. “Themore complex the hull form and features, themore challenging they are to clean, but overall the degree of difficulty doesn’t change toomuch,” Lander notes. The HSR has thrusters that allow it to be propelled manually like an ROV, and to attach itself to the hull using lowpressure suction. It then moves over the hull’s surface using its soft rubber tracks. “We did a lot of testing with the Florida Institute of Technology [FIT], choosing appropriate track materials,” Lander recalls. “We want good traction, but we don’t want to damage the paint on the hull, and we don’t want the tracks to wear out too quickly. It took a lot of lab testing there to figure out the right balance and settle on a suitable rubber compound.” Weighing around 30 kg and measuring about 86 cm long, the HSR is a small vehicle tasked with very large cleaning jobs. Lander explains that Armach wanted to keep it small so that it remains portable for one person, and can be launched and recovered without a crane or any other special equipment. “From there, it was a question of optimising the cleaning tool and robot speed to stay within that size limit,” he says. Rather than using batteries, the vehicle draws power via its tether from a generator ashore or aboard the ship it is cleaning. The tether is also the robot’s comms link with Armach’s mobile operations centre. Armach Robotics HSR | In operation By keeping a ship’s hull clean of biofouling we can significantly improve fuel efficiency as well as limit the potential of transfer of invasive species Uncrewed Systems Technology | June/July 2023 Forward-facing lights, cameras and multi-beam imaging sonar help with navigation, identifying objects and anomalies on the hull and avoiding obstacles
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