Flight dynamics of aerial vehicle considering time-varying ambient wind

Novel equations of motion for aerial vehicles considering the effect of continuously differentiable time varying ambient winds are proposed. The equations of motion consist of the aerodynamic angles and the inertial flight path angles as state variables. They cover a large range of ambient wind speeds without any approximation or linearization. Two unique angles of sequential rotations called the path-relative wind angles are proposed to parametrize the difference between the air-relative velocity and the inertial velocity caused by ambient wind terms. Moreover, since the conventional aerodynamic roll angle is no longer well-defined in a wind condition, a compatible modified version is proposed as well. The resulting state equations are structured to form a cascade system, which helps designers interpret the physical and geometrical meaning of individual subsystems and efficiently design a corresponding feedback control law. The model particularly fits motion control problems such as trajectory tracking or path following control of fixed-wing-type aerial vehicles in the presence of time-varying ambient wind. The properties and potential of the proposed formulation are discussed in depth by focusing on the meaning and use of each proposed angle and the wind estimation techniques. Numerical examples demonstrate the usefulness of the proposed model by showing how existing high-performance flight controllers initially developed for windless environments can be reused for windy environments while keeping their overall performance and formulation. (C) 2022 Elsevier Masson SAS. All rights reserved.