Agile maneuvering with a small fixed-wing unmanned aerial vehicle

This paper presents a general and systematic approach to automating a variety of agile maneuvers with a small fixed-wing unmanned aerial vehicle. The methodology begins by numerically solving optimal control problems off-line to generate a small set of reference trajectories and feedforward control inputs for maneuvers. A dynamic time warping-based interpolation process parametrizes these solutions, adding robustness to the maneuver, whilst allowing the on-board library of state and control time histories to remain compact. To handle errors, inaccuracies, noise, and disturbances that are not accounted for by feedforward control, feedback control laws stabilize about the reference trajectories. The work focuses mainly on one agile maneuver: an aggressive turn-around, in which the aircraft undergoes a rapid 180 degree heading reversal, beginning and ending in straight and level flight. To establish the generality of the methodology, it is also applied to transition maneuvers between straight and level flight, and a nose-up hover. The proposed automation scheme is computationally light during flight, consisting of a simple feedforward/feedback controller coupled to a compact library of maneuvers that are optimized over the full flight envelope. The methodology is validated in simulations and flight tests. The automation scheme is implemented successfully on a small fixed-wing unmanned aerial vehicle. (C) 2019 Elsevier B.V. All rights reserved.