Unmanned Systems Technology 019 | Navya Autonom Cab | Batteries | UGVs Insight | UAV Factory UAV28-EFI | Swiss Aerobotics Hummel | UMEX 2018 report | Antennas | Oceanology International 2018 report

Ireland-based Xocean debuted its XO-450 USV, a 750 kg vessel with a wave-piercing catamaran-type composite material hull. The hull shape was chosen to maximise the stability of the craft, with the two outer pontoons providing structural support and designed to be slender to present minimal resistance. Along the centre of the vessel is a housing containing a hybrid power system, including a lithium-ion battery. The vessel entered development in mid-2017, and the prototype began sea trials and system testing in January. “We’ve now started work on the second model, which will feature minor weight reductions in key areas to improve range and endurance,” James Ives said. “Apart from that, the prototype has performed according to our simulations in 3D CAD and finite element analysis.” The XO-450’s battery forms part of the hybrid propulsion system, which also uses solar cells on the deck and a micro-diesel generator to power two DC electric drives. MSI Transducers attended the event with its parent company Airmar Technology to showcase its injection- moulded piezocomposite solutions for underwater subsystems. “MSI injection-moulds ceramic pre- forms, which it uses in high-bandwidth transducers capable of withstanding significant ocean depths,” Ryan 94 Show report | Oceanology International 2018 Pellecchia said. “Piezocomposites, by their very nature, give you a broader bandwidth. This, coupled with MSI’s thermal polymers, allows us to manufacture acoustic comms transducers with 100% duty cycles – they can be in active operation for the full length of UUV missions.” The company’s standard piezocomposite transducers are designed to operate at a resonance of between 15 kHz and 600 kHz. They can be used for UUV multi-beam echo sounders, synthetic aperture sonars and sidescan arrays. Tecnadyne exhibited its range of UUV thrusters at the show. The Model 8050, the company’s newest system, features a magnetically coupled triple- bladed propeller that requires no rotating shaft seals – only seawater bearings – reducing maintenance requirements. Brandon Leap commented, “The 8050 is optimised for AUV applications. The thrust is at its most efficient at a speed of 10 knots, with 108 kgf. ROV-type thrusters are designed more for bollard thrust while being towed by a vessel and cable, not for AUV-type speeds.” The 8050’s design features an open (unshrouded) propeller design to avoid limitations in efficiency and manoeuvrability that might occur with a ducted propeller at 10 knots. A planetary gearbox is also integrated to reduce torque down to the motor section. “That allows us to use a smaller motor, as we’re not coupling directly to the propeller,” Leap added. “It also lets us integrate our own motor controllers inside the thruster itself, for depths down to 1500 m. The AUV designer only needs to interface for power and commands.” Blue Robotics also featured its thrusters for UUV and USV propulsion. The T100 and T200 are named for their originally intended power ratings, although the T100’s maximum power output is 135 W, and the T200’s is 350 W. The T100 can generate 2.36 kgf (kilogramme-force), while the T200 is capable of 5.1 kgf. Both are constructed from injection-moulded polycarbonate and use 316 stainless steel fasteners. “They’re fully flooded motors, as opposed to being sealed in a tube, so there’s no enclosed air or oil inside,” said Rustom Jehangir. “That enables a depth rating of at least 1000 m – we have not April/May 2018 | Unmanned Systems Technology An example of a piezocomposite underwater transducer from MSI Transducers The Tecnadyne 8050 thruster, showing its magnetically coupled propeller The XO-450 from Xocean features a wave-piercing hull to aid stability