Uncrewed Systems Technology 048 | Kodiak Driver | 5G focus | Tiburon USV | Skypersonic Skycopter and Skyrover | CES 2023 | Limbach L 2400 DX and L 550 EFG | NXInnovation NX 100 Enviro | Solar power focus | Protegimus Protection

53 SWL Robotics Tiburon | Digest Naturally, high speeds are not a strict requirement for survey USVs, and in fact can be detrimental to the density and quality of sensor data. The motor is therefore not intended to propel the airboat quickly, but will instead enable much heavier combinations of onboard sensors, since numerous SWL customers have increasingly asked to use payload sensors of greater weight and power than Enriquez and his team had originally anticipated. To ensure enough runtime for surveying large areas of sea and offshore assets (and prevent the mothership having to constantly retrieve Tiburons that have run out of energy), the batteries will be augmented with Honeywell’s 1.2 kWUAS fuel cells, specifically the kind we investigated in UST 46 (October/ November 2022). SWL is now in discussion with Honeywell to fit at least 600Wof the cells in the Tiburon, with the main constraint on the hydrogen powertrain being the amount of space to be occupied by the tank of compressed hydrogen. “We anticipate a minimum endurance of 4 hours at full load, although we don’t expect anyone to operate a Tiburon at full load for the full length of any mission. In fact we’re going to integrate an anchor system, nothing too long or heavy, so that the vessel can station-keep for extended point surveys without needing to power its motor,” Enriquez adds. “Realistically, we could get a maximum reliable endurance of up to 10 hours using those fuel cells, between refuels and recharges. And if we choose to integrate solar panels as well, we’ll obviously push that further.” In order to manage their current and future electric motors with the degree of torque control and dynamics desired, SWL selected motor controllers from APD. These have added capacitor banks for protecting the motor controllers from the current peaks that higher-torque electric machines inevitably produce. SWL adds that the ability to tweak and customise themotor controller to its specific use was key to its selection of APD controllers. “We also find they are being used in UAVs with similar end-users to our target demographic,” Enriquez notes. The hull As discussed, the Tiburon is made not from fibreglass, as is most common for marine vessels, but carbon composite, a crucial component for saving weight in its body. Enriquez describes the body as “important, but not directly adding to the craft’s capabilities, unlike the computers and sensors”, and the weight saved in the hull is allocated accordingly to the payload capacity. SWL’s partner here is Citius Composites, which had previously cut its teeth on Lockheed Martin’s VTOL UAVs, with considerable work specifically going into the aircrafts’ battery containment sleeves. “The battery’s enclosure is of course a safety-critical component for containing harmful gases or sparks in the event of a crash, but we have also looked into ways of saving weight in the motor stand, the motor shroud, really any of the material sections on the craft,” Enriquez explains. “And when we seal the craft, it effectively becomes a monocoque, one that’s strong and feels like a solid, single piece of composite. That’s important, as the vessel needs to endure impacts well and keep functioning.” Along with Citius’ carbon fabrics and manufacturing, SWL selected resin systems from its preferred supplier Scot Bader as the matrix material. The resin of choice is more flexible than most, in order to reduce the brittleness that CFRP can exhibit. Uncrewed Systems Technology | February/March 2023 At present, power comes from a 400WBLDC electric motor, although a 2.4 kWmotor is lined up for the next version of the USV With a lot of lithium- ion batteries, you find that the voltage decreases as the battery discharges, so you start to lose power over the mission’s runtime