Experiments in Fixed-Wing UAV Perching

High-precision maneuvers at high angles-of-attack are not properly addressed by even the most advanced aircraft control systems. Here we present our control design procedure and indoor experimental results with a small fixed-wing autonomous glider which is capable of executing an aggressive high angle-of-attack maneuver in order to land on a perch. We first acquire a surprisingly accurate aircraft model through unsteady flight regimes from real kinematic flight data taken in a motion-capture arena. This model is then used in a numerical nonlinear (approximate) optimal control procedure which designs a feedback control policy for the elevator deflection. Finally, we report our experimental data demonstrating that this simple glider can exploit pressure drag to achieve a high-speed perching maneuver. Nomenclature x Horizontal position, m z Vertical position, m θ Pitch angle of fuselage and wing, in the lab frame, radians ψ Elevator deflection angle, in the fuselage frame, relative to trim, radians