Cascade-Like Modular Tracking Controller for non-Standard N-Trailers

A general trajectory-tracking control solution is proposed for truly N-trailer robots comprising a unicycle-like tractor and arbitrary number of passive trailers interconnected by sign-homogeneous nonzero hitching offsets. The solution permits either backward or forward motion strategy of a vehicle, preserving location of a guidance point on the last trailer. The presented control law is modular and highly scalable with respect to a number of trailers thanks to employing a cascade-like control structure. Stability and robustness analysis of the closed-loop system provides sufficient conditions for asymptotic and practical tracking for a wide set of the so-called segment-platooning reference trajectories containing both constant-curvature and varying-curvature motion profiles. Efficiency of the controller and its robustness to parametric uncertainty have been illustrated by experimental results obtained for a three-trailer vehicle.