Ground manoeuvres of aircrafts in narrow spaces by all-wheel-steering

The present analysis deals with the ground taxiing of aircrafts and considers, in particular, their turning at rather low speed with very small path radii among obstacles that may be very close to each other, for example inside the hangars or on the flight decks of the aircraft carriers where other planes stand stationary. To succeed in this operation, it is crucial to optimize the path and avoid dangerous collisions or, more generally, the interference in the ground projection between the obstacles and the band enclosing all the point trajectories of the plane. The essential innovation here proposed for this purpose consists in making all the wheels of the undercarriage steerable, assuming electrically motorized struts, and in searching for the best correlation among the steering angles in order to optimize the path. The geometrical and dynamical nonlinearities due to the relatively large steering angles, to the changes of the cornering stiffness with the vertical loads on the wheels and to the inertial and the aerodynamic forces will be included in the analysis. The rollover critical speeds will be calculated on varying the path radius.