Unmanned Systems Technology 018 | CES show report | ASV Global C-Cat 3 USV | Test centres | UUVs insight | Limbach L 275 EF | Lidar systems | Heliceo DroneBox | Composites

52 USA, and remains on hold. A US Navy statement at the time confirmed how Boston Engineering’s tuna-sized device had been gathering data at JEBLC-FS on “…tides, varied currents, wakes and weather conditions for the development of future tasks, allowing the Navy to achieve success during more types of missions while keeping divers and sailors safe”. The GhostSwimmer is 5 ft in length with an all-up weight of 100 lb, and allowed operators to operate in waters from 10 in depth down to 300 ft. A statement from the US Navy Warfare Development Command, which is responsible for rapid prototyping of next-generation capabilities in support of maritime operations, explained at the time of testing, “Its bio-mimicry provides additional security during low- visibility intelligence, surveillance and reconnaissance missions and friendly hull inspections, while [being] quieter than propeller-driven craft of the same size.” The UUV could be operated autonomously as an AUV as well as in a tethered configuration as an ROV with 500 ft cabling for longer operations. However, similar to submarines that lack specialist underwater and on-the-move comms payloads, the GhostSwimmer would be forced to surface in order to network any intelligence data back to an operations centre for processing, exploitation and dissemination. Despite not being further pursued by the navy, the Silent Nemo programme illustrates what is possible with bio- mimicry UUV technology, providing impetus to future programmes. These include a similar biomimetic concept being explored by the NUS, which in November 2017 announced the development of a UUV concept based on the manta ray. Developed with a requirement to have a mission duration of up to 10 hours, the so-called MantaDroid mimics the natural movements of the manta ray. Associate Professor Chew Chee Meng, of the Department of Mechanical Engineering at the Faculty of Engineering at the NUS and programme manager for MantaDroid, says the AUV has already achieved Technology Readiness Level 6, which he says allows it to operate in shallow waters. The current prototype, designated MantaDroid Mark I, does not have a tail fin, and measures 35 cm in length. With an all-up weight of 700 g, it can also carry an extra payload of up to 800 g, Associate Professor Chew says.  However, the NUS has also designed a second variant, the MantaDroid Mark II, which does include a tail fin. Measuring 54 cm in length (excluding its tail), Associate Professor Chew claims it has a maximum payload capacity of 5 kg, and says it will be used for the further study of the scalability of key design parameters and design trade-offs in biomimetic AUV technology.  As he explains, “Once we have understood the design scalability and completed the motion control study for the Mark II prototype, we will work on a remote-control subsystem and eventually turn the robot into an autonomous system, which is important February/March 2018 | Unmanned Systems Technology Boston Engineering has developed the GhostSwimmer and BioSwimmer (illustrated) UUVs, which mimic the oscillating movements of a tuna fish for propulsion (Courtesy of the US Office for Naval Research)