Issue 45 | Uncrewed Systems Technology Aug/Sept 2022 Tidewie USV Tupan | Performance monitoring | Bayonet 350 | UAVs insight | Xponential 2022 | ULPower UL350i and UL350iHPS | Elroy Air Chaparral | Gimbals | Clogworks Dark Matter

34 Dossier | TideWise USV Tupan “We’ve just started working on the obstacle detection and avoidance, and we’ll probably have the first trials next year,” he adds. “It needs to meet high technical targets for its performance before we can trust using it in customer missions, because the marine environment is prone to very dynamic changes in light levels and operational conditions. Rain, fog, sunlight, traffic, reflections and clouds or landscapes in the background can have dramatic effects on perception systems.” A combination of convolutional neural network-based image training and (less complex) heuristics-based classification is used for TideWise’s object recognition. The team notes that such algorithms are less intensive at sea than on roads owing to the visually simpler scenes to be processed. And apart from obeying COLREGs, the low speeds that vessels adhere to when operating around critical infrastructure mean obstacle avoidance is less safety- critical than in highly congested and dynamic road environments. “The key thing is that we can detect and classify objects with our cameras, then transmit that data to the main computer, faster than a Lidar would,” Coelho says. The data comms and control outputs throughout the Tupan are handled largely over an Ethernet network. When devices aren’t Ethernet-based, the USV has the capacity to interface with RS-485 or CAN on the main computer. Alternatively, the team can add a small single-board computer to interface with sensors or actuators, and hence provide a software route to it. TideWise opts for the industrial version of the BeagleBone Black from TI’s BeagleBoard family. “This is sometimes also done to reduce or facilitate cabling requirements,” Joyeux says, “For instance, the main propulsion motors communicate over RS-485, but the rudder’s motor controller is CANOpen. Other sensors might be analogue, NMEA2000, NMEA0183 or similar.” Diesel-hybrid power “The Tupan, being a diesel-electric vehicle with differential thrust, can keep fuel consumption extremely low, especially in station-keeping operations,” Coelho comments. The thrust is provided by two customised electric motor and propeller drives from Brazil-based WEG. Each one provides up to 3 kW of power at a speed of 1800 rpm. Steering meanwhile is performed by Jefa-brand rudders controlled by a Roboteq DC motor controller. “In addition to robustness, we saw configurability and feedback as being the most critical considerations for our motor controllers,” Coelho says. “They were key throughout the powertrain – all our gears are ruggedised for industrial use, for instance – and the motor controllers had to be able to withstand significant levels of temperature and current for long periods without it affecting their MTBFs too much. “I think Jefa’s steering components are the best in the world, really reliable. The main commercial marine autopilot suppliers – Garmin, Raymarine, the list goes on – all buy from Jefa, sometimes just with a different label.” Joyeux adds, “Right now, we can go from 0 to 3 kW in 4 seconds. That’s quite a bit of current to push, even for a company as experienced in electric motor engineering as WEG. “As well as robustness, we wanted our motor controllers to be smart – that is, to give detailed health and performance data for trialling and diagnostics, anything that could help us verify that the USV is working as it should be, and to carry out predictive maintenance in the future.” A 48 V pack of four 185 Ah lead-acid batteries is installed for distribution of stable electric power to the thrusters and elsewhere. Coelho adds that current marine regulations in Brazil were the main blocker to not using LiFePo cells, but with more recent changes in regulations, TideWise is now designing a fully electric version of the Tupan for a couple of clients. The diesel generator recharging the battery is the Piccolo 8 from Netherlands- based WhisperPower. The generator produces up to 6 kW of continuous power, and runs on a Kubota Z482, a 479 cc two-cylinder four-stroke with inductive discharge ignition, a permanent magnet alternator and water cooling. WhisperPower’s DC Cube system meanwhile steps the voltage down from 120 to 230 V AC to 48 V DC for the battery. The generator also features sound guards to reduce audible noise and its impact on sonar and antenna reception, advanced diesel engine suspension to reduce vibration, and an integral liquid- cooling system. It also comes with its own ECU and a BMS. August/September 2022 | Uncrewed Systems Technology TideWise’s proprietary WiseBridge software is used for the Tupan’s user interface and GCS