Coupled Flexible and Flight Dynamics Modeling and Simulation of a Full-Wing Solar-Powered Unmanned Aerial Vehicle

The full-wing solar-powered unmanned aerial vehicle (UAV) adopts a large aspect ratio wing, a lightweight structural design, and a differential throttle control scheme to maximize flight endurance. Large structural deformation often occurs when the wing is heavily loaded, which affects its flight stability, trajectory tracking accuracy, and flight performance. The traditional rigid-body flight dynamics cannot accurately describe the actual dynamic behavior when the wing is deformed. To fully consider the coupling effect of the structural deformation and the flight motion, we derive a UAV combo model consisting of a flexible wing and rigid fuselage. In the model, we also include strain formulation (s-beam) for structural modeling, finite-state induced flow theory for aerodynamic modeling, static and dynamic combined experiments for engine modeling, and the rigid-body flight dynamic equation. Besides, a model modification method based on flight data is applied to improve the accuracy of the structural parameters. Simulation results show that the wingtip deformation and motion characteristics of the rigid- and combo-system are quite different: the combo model exhibits a certain lag in comparison with the rigid-body, with the amplitude of the motion parameters reduced by 50%, frequency 15%, system kinetic energy 11.8%, and the elevator control efficiency more than 40%.