Collision-free navigation of N-trailer vehicles with motion constraints

In this work, a collision-free navigation strategy for N-trailer vehicles is proposed. This approach is based on a scalable cascaded control scheme to perform several tasks simultaneously: trajectory tracking control, off-track error reduction, external obstacles avoidance, and inter-vehicle collision avoidance. To validate the proposed strategy, a Generalized N-trailer (GNT) structure with a car-like tractor and 10 trailers is tested in simulation to track an U-shape trajectory in presence of unknown obstacles, similar to the trajectories that agricultural vehicles must perform in real applications. The well-known information about external infrastructure is also considered to reduce unsafe trailers off-track errors in turning scenarios. Moreover, the motion constraints imposed by the car-like tractor physical limitations and the interconnections between trailers are also considered by restricting the control input in order to avoid collision between trailers. The simulation results obtained showed a safe navigation which performed feasible maneuvers without collisions between the vehicles' chain and any trailer or external obstacle.