Tractor-trailer path generation in three-dimensional space based on Bezier curve and geodesic theory

Tractor-trailers are commonly used to load large cargoes onto roll-on and roll-off (Ro-Ro) ships. To safely load cargoes to the target position on the deck, the path of tractor-trailer needs to be designed for avoiding collision with obstacles. During the loading process, tractor-trailer has to through the inclined ramp which connects the horizontal dock with deck, and the path must be designed in three-dimensional (3D) space. Based on the dynamic relationship between tractor and trailer, the collision free path generation for tractor-trailer on two-dimensional (2D) plane could be realized. However, the proposed methods cannot appropriate for analyzing the motion of tractor-trailer in 3D space. This research investigated a method to generate the safest loading path of tractor-trailer in 3D space. First, the loading scenario was divided into seven sections and all the possible tractor paths were generated based on the Bezier curves. Next, the conversion of tractor-trailer dynamic relationship between 2D plane and 3D space was realized by using geodesic theory, and the trailer paths were calculated according to tractor paths. Then, all paths are sorted based on transportation efficiency and safety during the transportation process. Finally, collision detection is carried out on the generated paths in sequence to determine the safest loading path for the tractor-trailer. Simulation and experimental results verified that the proposed method could be used to design the loading path of tractor-trailer in 3D space under multiple scenarios.