Effective Angle of Attack Measurements in Active Control for Vortex Gust Mitigation

Gust encounters can have adverse effects on the flight stability and trajectory of air vehicles. These effects are particularly pronounced for Micro Air Vehicles (MAVs) which generally fly at velocities of the same order of magnitude with the flow velocity changes induced by atmospheric gusts. This study proposes and experimentally demonstrates the use of effective angle of attack measurements taken from upstream of a NACA0012 wing that is exposed to a continuous vortex gust generated by the wake of an upstream cylinder for the mitigation of gust-induced loads by feed-forwarding the measurements to actuate a trailing edge flap to exploit the temporal gap between the measurement and the force development in the air. Follow-up water channel experiments have been performed to verify the validity of the measurements performed in the air. It was seen that feed-forwarding the angle of attack measurements in water fails due to the added mass effects present in the medium. An ODE solution was implemented to work around the issue and, through a few iterations, a force mitigation of 74.40% was achieved.