Minimum time trajectories for a class of V/STOL aircrafts

This paper focuses on the problem of achieving a minimum time transition between two remote hover points, considering a class of tail-sitter V/STOL (Vertical / Short Take-Off and Landing) aircrafts capable of combining both the hover flight and the level flight. The distinguishing feature of such systems is to succeed in operations which require high precision and stability - such as flying next to infrastructures, autonomous takeoff and landing, etc. - and, at the same time, to be able to minimize the total energy and the total time required to reach the location in which the operation is achieved. After deriving an approximated dynamical model for the system's dynamics considering explicitly the hover and the level flight envelopes, the problem is addressed by computing the necessary optimality condition according to the Pontryagin minimum principle. The proposed explicit solutions can be employed to estimate or bound the cost of a point to point maneuver, and then to be part of more general path planning scenarios.