Multibody-Dynamic Modeling and Stability Analysis for a Bird-scale Flapping-wing Aerial Vehicle

In this work, we present a new mathematic model for the flight of a bird-scale flapping-wing aerial vehicle, in which the impacts of the wing inertia and its deformations are considered. Based on this model, the longitudinal and later-directional orbit stability of the vehicle at uncontrolled condition are proved to be steady via Floquet Theory combined with the untethered flight experiment. However, both simulation and experiment show that the vehicle presents a periodical motion state which is similar to spiral flight at uncontrolled condition. At this spiral-like flight state, the yaw angle of the vehicle varies constantly, which makes it difficult to meet the requirements of the general flight mission. In this case, two independent PID controllers are designed to stabilize the vehicle attitude based on the approximate linear model in the vicinity of the equilibrium flight condition. And the controlled flight of the vehicle prototype is also proved to be stable through numerical calculation and physical experiment.