Unmanned Systems Technology 036

48 Insight | UUVs at the back. Three additional vertical thrusters are integrated into the body and oriented for pan and roll manoeuvres, and covered with grilles to prevent interference with the hydrodynamics. EvoLogics says the vehicle has been developed within the framework of the MUM (Modifiable Underwater Mothership) r&d project, which is coordinated by Thyssenkrupp Marine Systems and funded by the German Federal Ministry for Economic Affairs and Energy. As with the Flying Nodes, EvoLogics anticipates the PingGuins being operated in swarms, potentially acting as comms nodes or for long baseline (LBL) positioning. They would swim down to the seabed to serve as baseline transponders, rather than requiring divers to place them by hand – a lengthy and potentially dangerous exercise. For LBL positioning, an anchor mechanism would extend from the PingGuin’s body to keep it stationary on the seabed. Also, its ‘beak’ has a gripping mechanism for potential use with docking systems. Other onboard systems include an EvoLogics ultra-short baseline (USBL) modem for subsea data transfers and position estimates, and an atomic clock for synchronising acoustic networks. A dorsal comms module incorporates wi-fi, radio and GNSS links, all of which use a combined collapsible antenna. An Iridium or GSM modem can also be fitted. In an even more striking example of unmanned seabed operations following biological evolution, researchers at the BioRobotics Institute in Italy are developing a crab-like robot as an alternative to conventional pelagic (swimming) UUV designs. In the absence of an effective landing or anchoring solution, their six-legged Silver2 UUV is designed to stand securely on the seabed and then lower its body – which includes a frontal camera and sampling devices – onto the surface. Embedded software contains the necessary calculations for walking over key points of interest, and it propels itself by ‘hopping’ along the seabed. Its legs contain electric motors with XM430- W350-R Dynamixel actuators for motion, and piezoelectric transducers for sensing touchdown and lift-off. Trials of the Silver2 so far have included 10 missions over various types of seabed, including those with rocks, sand dunes and seaweed, and it has travelled effectively across all of them. Telemetry and control of the system is achieved via a wireless buoy that provides a wi-fi connection between the robot and the researchers’ control station. Harbour operations In another advance for the viability of UUVs, testing, inspection and certification organisation Bureau Veritas has completed its proof-of-concept project for unmanned underwater ship hull surveys, using the Seasam UUV from Notilo Plus. The AUV/ROV hybrid craft was used to inspect the Mediterranee , a car ferry belonging to transportation company Corsica Linea. It was an important proving case for underwater robotics manufacturers aiming to supply UUVs as a more efficient substitute for divers or other conventional methods for locating hull damage, biofouling or other causes for concern. The inspection tool used on the Seasam was a 1/2.8 in (0.9 cm) CMOS Sony IMX290 camera. When combined with a tether for data comms, video could be streamed to the end-user at 1080p HD image quality at 30 fps, with 2 MP still imagery capturable. For helping with underwater inspections, particularly to illuminate areas on the undersides of ships’ hulls or other subsea structures, the 9 kg robot comes with two 1000 lumen lights with a 110 º beam angle. This February/March 2021 | Unmanned Systems Technology The Seasam has been used in a successful trial for ship hull inspections (Courtesy of Notilo Plus) In one example of unmanned seabed operations following biological evolution, researchers in Italy are developing a crab-like UUV design