Autonomous Wind Tunnel Free-Flight of a Flapping Wing MAV
A low-cost high performance control system is developed to enable autonomous untethered flight inside a wind tunnel. Such autonomous flight is desirable for aerodynamic experiments on flapping wing MAVs, since fixing the fuselage has been shown to significantly alter wing deformations, air flow and performance on vehicles with a periodically moving fuselage. To obtain autonomous untethered flight, 3D position information is obtained from off-board WiiMote infrared tracking sensors with a total system accuracy of 0.8mm and an update rate of 80Hz in a quarter cubical meter control box. This information is sent to a 1.5 gram onboard autopilot containing communication, inertial measurements as well as onboard infrared tracking of an in-tunnel LED to achieve the high performance control needed to position itself precisely in the wind tunnel flow. Flight tests were performed with the 16 gram flapping wing MAV DelFly II. The achieved control performance is shown to be sufficient for many new research purposes, like researching the influence of a fixed fuselage in flapping wing aerodynamic measurements and obtaining more precise performance characteristics.