Performance Improvement of Small UAVs Through Energy-Harvesting Within Atmospheric Gusts

Abstract : Fixed-wing mini aerial vehicles usually at low altitudes often exposed to turbulent environments. Gust soaring is a flight technique of energy harvesting in such a complex and stochastic domain. Presented work shows the feasibility and benefits of exploiting non-stationary environment for a small UAV. Longitudinal dynamics trajectory is derived showing significant benefits in extended flight with sinusoidal wind profile. Optimization strategy for active control has been performed with the aim of obtaining most effective set of gains for energy retrieval. Moreover, three-dimensional multi-point model confirmed feasibility of energy harvesting in a more complex spatial wind field. Influence of unsteady aerodynamics is determined on overall energy gain along the flight path with active proportional control. Most contributing aerodynamic parameters are identified and suggested as basic objective function of an UAV design for energy harvesting in gusty environment. In addition, passive approach of control related to structural dynamics is investigated, pointing out its potential and possible improvements with aeroelastic tailoring.