Shape of things to comeRobot aircraft rides thermal currents to save fuel

Published 25 August 2008

Soaring birds use thermal air currents to keep them aloft for hours and save energy; the same principle is now being applied to UAVs

We have written about how engineers often emulate nature and its creatures in order to achieve better results — see, for example this HS Daily Wire 22 May 2008 story about robotic grasshopper; or this HS Daily Wire 19 September 2007 story about a mecahnical mole. Glider pilots harness upward-moving thermal air currents to keep them aloft for hours, while soaring birds use them to save energy. Unmanned aerial vehicles may soon borrow the same technique to save precious fuel, using software that identifies regions of rising air. “It could increase the vehicles’ endurance during surveillance missions,” says Rhys Watkin of Roke Manor Research in Hampshire, United Kingdom, a member of the team that developed the system.

To seek out nearby thermal currents, the software first analyzes video of the sky taken by an on-board camera. It searches for the telltale grey, dome-shaped clouds which are formed by rapidly rising hot air. The system combines this with real-time weather forecasts and computer simulations of air flow across the local terrain to predict the locations of further thermal currents. The team also fed the software information from anecdotal reports by expert gliders, highlighting areas of rising air in specific locations and in various weather conditions.

During a mission, the software uses all of this data, together with the aircraft’s GPS coordinates, to plan a route that passes through as many thermals as possible. So far, the system has only been used to suggest the path for a glider pilot to follow, but the team is developing software to enable an autonomous vehicle to fly solo. In the future, Watkin hopes to add further software which will analyze maps of the local area and estimate how well ground surfaces emit heat, which also helps predict the location of thermals.