Perching trajectory optimization using aerodynamic and thrust vectoring

This paper presents and compares individual and concurrent use of aerodynamic and thrust vectoring features to optimize perching trajectories. An optimization framework is first developed to compute perching trajectories to transfer an aircraft from a level-flight trim state to a perched state in the least covered flight-path. Rotational freedom is given to the outboard section of the wing and directional freedom is given to the thrust to provide aerodynamic and thrust vectoring features to the aircraft, respectively. Through combinations of these two features, four configurations including aerodynamic vectoring only, thrust vectoring only, coupled and uncoupled aerodynamic and thrust vectoring, are framed. Optimal perching trajectories are computed for all the configurations and the results compared with the corresponding fixed-wing trajectories. It is shown that all the unconventional configurations reduce the spatial bounds of the perching maneuver. The least minimum undershoot is achieved with the uncoupled aerodynamic and thrust vectoring configuration and followed closely by the thrust-vectoring only configuration. Owing to the ease of operation and the ability to generate minimum undershoot trajectories, the use of thrust vectoring alone is recommended for achieving optimized perching maneuvers.