The ability of multiple unmanned air vehicles to flock like birds by entering formation without colliding has been demonstrated by Atair Aerospace in tests of its Onyx autonomously guided parafoil system. The test involved five of the cargo-carrying UAVs, which are in production for the US Army, writes Graham Warwick.
Atair has implemented flocking and active collision avoidance algorithms in the control system of the Onyx UAV. Initially, after release from the aircraft, the system is in a learning phase, during which it adapts to the characteristics of the suspended load.
It then enters the flocking phase, in which it follows the UAV closest to the target.
Guidance is based on blending vectors to the lead UAV and the target, and the system can be programmed to form a tight or loose flock, says Atair chief executive and lead engineer Dan Preston. The UAVs communicate with each other and a laptop base station via cellphone-like datalink.
As the UAVs swoop down on the target, they each time their entry and exit from a spiral dive to reduce the possibility of conflict. If the control system detects a conflict between two UAVs, guidance is suspended and one or both executes a right turn. "Active collision avoidance is not used 90% of the time," says Preston.
Single-system Onyx UAVs now being delivered have a landing accuracy of 57m (187ft), says Preston. A distance between UAVs of 50m was set for the flocking demonstration, and resulted in a landing accuracy of 150-170m – in part because the tests took place in high winds, he says.
Atair plans around 200 drop tests before fielding a flocking upgrade to the Onyx.
Source: Flight International
