Trailer-Maneuverability in N-Trailer Structures

The letter presents a trailer-maneuverability analysis for the N-trailer kinematic structures comprising a tractor and an arbitrary number of single-axle trailers equipped with steerable or fixed wheels. For an elliptically-shaped set of tractor's input-velocities, we derive a mobility-ellipse generated in a velocity space of the (last) trailer. We show that the on-axle type of hitching present in the N-trailer leads to a singularity of a trailer-mobility (at least one degree of mobility is lost). Furthermore, we provide some relations between kinematic parameters of the N-trailer and its control inputs which enable shaping the trailer-mobility ellipse and decoupling it from a joint-configuration of the vehicle.