An autonomous paraglider inspired by nature could help armies聽to resupply troops in dangerous places, or deliver humanitarian aid to disaster zones. The British Army trialled the unusual aerial vehicle during聽a recent month-long combat exercise.
Called Stork, the glider can take off and land in very tight spaces. It聽can fly itself to preprogrammed coordinates, using either GPS or a vision-based navigation system if GPS is not available.
Stork鈥檚 small, three-wheeled chassis has a motor for propulsion. When airborne, both are suspended from a paraglider wing that fills with air as it moves forward. The aerofoil shape of the聽wing was inspired by the aerodynamics of eagles鈥� wings.
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Paragliders are a rare example from engineering of a hydrostatic skeleton, a structure supported by聽air or liquid. The idea is the basis for a wide variety of biological structures from the bodies of worms to human tongues, and it has benefits for聽industrial design, as well.
鈥淚t means you鈥檝e got a wing you聽can pack into a tiny bag and it聽weighs almost nothing,鈥� says Adrian Thomas, a four-time UK paragliding champion and co-founder of Animal Dynamics, the聽company that created Stork.
Bird-like behaviour
Stork鈥檚 navigation systems are聽also influenced by animal behaviour, such as the way pigeons use features on the ground to navigate. Like birds, the聽system avoids obstacles using the principle of optic flow: how quickly objects in the field of view get bigger as you travel tells you how far away they are.
The British Army put Stork through its paces by simulating delivery missions on Salisbury Plain in the UK. This involved parachuting packages on to the edge of a forest, or a house on the edge of a model town.
鈥淭hey were out in the wind and rain, managing to do autonomous deliveries in scenarios representing military missions and humanitarian aid delivery missions for a variety of loads,鈥� says Peter Stockel from the UK鈥檚 Defence Science and Technology Laboratory (DSTL).
The craft did well in challenging weather conditions, says Thomas. 鈥淚t was more successful than I thought was remotely possible.鈥�
One version of the paraglider weighs around 50 kilograms and can carry up to 30 kilograms. A聽larger version weighs 150聽kilograms and can lift up to 100聽kilograms, so could be used to聽evacuate casualties. Animal Dynamics plans to make even bigger models, which could carry trucks to hard-to-reach areas. Thomas expects to have Stork on聽the market in 2020.
Stork is one of five systems being evaluated in phase two of聽the Autonomous Last Mile Resupply competition, a DSTL-led project challenging commercial partners to develop technology to support military operations. The rivals include winged aircraft, quadcopters and ground vehicles.
Animal Dynamics also has DSTL funding to develop a tiny flapping drone based on a dragonfly, which could be used by soldiers for reconnaissance. It鈥檚 not yet ready for military testing, but in theory a flapping bot should cope with wind gusts better than rotor-based flyers such as the Black Hornet, a small drone the UK army uses now.
