Active and passive straightening control strategies for non-standard N-trailer vehicles

Maneuvers with articulated vehicles belong to the most demanding control tasks performed in every-day transportation practice. One of the most frequent maneuvers involve straightening of a vehicle chain during a preliminary stage which prepares the system to subsequent difficult maneuvers like backward docking with trailers. In this paper two alternative types of straightening control strategies (active and passive) are proposed and compared in view of their effectiveness in vehicle self-aligning. Control strategies are designed and analyzed by using the triangular forms derived for joint-angle kinematics of the N-trailer vehicle equipped with off-axle hitching interconnections. Formal considerations are verified by numerical tests.