A semitrailer is a trailer with its axle located behind the vehicle's center of gravity and connected to a tractor by a tow pin. It lacks power and relies on the tractor for propulsion, with the tractor bearing some of the trailer's weight. Semitrailers are a core component of modern road freight transport, occupying a crucial position in long-distance logistics thanks to their large payload capacity and flexible configuration. With advancements in lightweighting, intelligent technology, and new energy technologies, semitrailers are becoming increasingly efficient and environmentally friendly.