Unmanned Systems Technology 027 l Hummingbird XRP l Gimbals l UAVs insight l AUVSI report part 2 l O’Neill Power Systems NorEaster l Kratos Defense ATMA l Performance Monitoring l Kongsberg Maritime Sounder

7 Platform one An energy-efficient data routing algorithm developed by an international team could keep UAV swarms flying for longer (writes Nick Flaherty). In disaster support-and-recovery scenarios, when the local comms infrastructure has been destroyed, UAV swarms can be linked to one or more local base stations to provide comms links. Maintaining these links for as long as possible is essential. “The battery capacity of UAVs is a critical shortcoming that limits their use in extended search-and-rescue missions,” said team member Wuhui Chen, a researcher at China’s Sun Yat- Sen University. There is a major trade-off between the bandwidth requirements and the transmission time. So the team developed a data routing algorithm that uses multiple hops between members of the swarm. This hybrid computational approach combines mainstream linear programming (LP) with a genetic algorithm. The adaptive LP-based genetic algorithm (ALPBGA) identifies the lowest energy route within a swarm in real time and simultaneously balances out the individual UAV power use, for example Engineers at Southwest Research Institute, in the US, have developed a 3D-printed impeller for a cooled, radial gas turbine (writes Nick Flaherty). They say it can provide thousands of hours of electricity to a UAV – a significant improvement on current UAV turbines that operate for only a few hundred hours before wearing out. by determining which UAV will send information to a base station. “By balancing power consumption among the UAVs, we can significantly boost the ability of the whole system,” said Patrick Hung, a researcher at the University of Ontario Institute of Technology in Canada, and another member of the team. “Simulations show that our approach can outperform existing methods.” The simulations show that as swarm The problem with current small turbines is that during the combustion process the turbine has to withstand the high-temperature gas, which can cause damage. “We’ve designed a turbine that has tiny airflow passages that cool the turbine without sacrificing the power,” said David Ransom of the institute’s Mechanical Engineering division. “Normally with size increases from tens to hundreds of UAVs, the ALPBGA algorithm reduces the number of UAVs that stop communicating by 30-75% compared with other swarm communication algorithms. The next move is to extend the ALPBGA research to different swarm flying trajectories to see how the positioning of the UAVs in the swarm can further reduce the overall energy consumption. small turbines you have to choose between performance or reliability, but we’re making it possible to have both.” The engineers used the internal passages of large, high-temperature turbines found in power plants and passenger aircraft. To create the small, intricate design with internal air passages, they used selective laser melting, which builds metal parts layer by layer. Swarm endurance boost Cool idea for gas turbines Airborne vehicles Propulsion Unmanned Systems Technology | August/September 2019 The data routing algorithm minimises energy use for comms across a swarm of UAVs (Courtesy of Wuhui Chen)