Design and prototype production of reversing park assist for double-axle agricultural trai̇ler

In this study, the design, analysis, and prototype development of a reverse maneuvering parking assistant system for a double-axle agricultural trailer were carried out. The system limits the scissoring motion of the trailer's pivot mechanism during reverse maneuvers by enabling the drawbar to move linearly. Furthermore, to enhance maneuverability during reversing, the fixed rear axle system was equipped with steering capability using a double-acting hydraulic cylinder. The experiments were conducted in five different configurations: U1 (Standard pivot-type agricultural trailer), U2 (Rear steering and unrestricted pivot system), U3 (Rear steering and restricted pivot system), U4 (Rear steering, movable drawbar, unrestricted pivot system), and U5 (Rear steering, movable drawbar, restricted pivot system). Each configuration was tested with three different operators (OP1, OP2, OP3) and three replications. In the U1 configuration, due to the fully free pivot mechanism, the trailer experienced severe scissoring during parking maneuvers across all operators, resulting in the longest average parking time of 223 seconds. In the U2 configuration, the rear steering system enabled the trailer to be parked with minimal maneuvering, reducing the average parking time to 98 seconds. In U3, the restricted pivot mechanism forced the front axle of the trailer to skid during reversing, leading to an average parking duration of 133 seconds. In U4, an average parking time of 128 seconds was recorded. Thanks to the linear movement of the tractor's drawbar, scissoring was prevented as soon as the front pivot axle started to misalign. In U5, the combination of a movable drawbar and a restricted pivot system successfully prevented both scissoring and axle dragging during reverse maneuvers, resulting in an average parking time of 102 seconds.