Dump truck is a vehicle that unloads goods by hydraulic or mechanical lifting. Also known as a dumper. It consists of automobile chassis, hydraulic lift mechanism, cargo box and retraction device. The car of the dump truck is divided into two types: backward overturning and lateral overturning. The movement of piston rod is controlled by the control system. The backward tilting is more common, and the piston rod is pushed to make the car overturn and a few of them are bidirectional overturned.