Marine crane is a special crane for transportation in marine environment. It is mainly used for important tasks such as the transportation and transit of goods between ships, the replenishment at sea, and the release and recovery of underwater operation equipment. The special application environment at sea brings great challenges to the control of marine cranes. On the one hand, similar to all kinds of underactuated crane equipment on land, it is necessary to control the swing during load transportation to ensure its positioning accuracy and transportation efficiency; On the other hand, because the crane is fixed on a mobile platform such as a ship, the movement of the platform itself has a strong influence on the negative movement of the load. In many cases, the movement of the lifting point and the landing point of the load is inconsistent with the movement of the crane itself. Specifically, in the process of work, the crane ship and the receiving ship will pitch, roll and heave with the waves, thus causing the load to swing; Especially in the process of lifting, this movement of the ship is likely to cause the lifted goods to collide with the deck again, or make the goods that have been put down but have not left the hook hang up again, thus threatening the safety of operation. Especially in the ammunition supply between ships, this coupling movement may cause very serious consequences.

In recent years, the control of ship crane has attracted extensive attention of military and civil marine engineering in various countries. It is also of great theoretical value and universal significance to study the control of this kind of nonlinear and strongly coupled underactuated system under special disturbance.

The control of marine crane is mainly divided into two aspects: vertical control to reduce the influence of hull motion and lateral anti-swing to suppress load swing. For vertical control, the common method is to connect the receiving ship through the mechanical structure of the crane ship and sense its relative motion, so as to synchronize the length change of the lifting rope with the heave motion of the receiving ship, thus compensating the relative motion of the two ships, and on this basis, complete the take-off and landing transportation of the load. This method has special requirements for the mechanical structure of the crane and great restrictions on the lifting quality. Kuchler and other scholars established a dynamic model of underwater equipment lifting process. They consider the elasticity and hydrodynamic force of the suspension rope, and design a trajectory tracking and interference suppression controller based on feedback linearization method. Johansen and others used the wave synchronization technology based on feedforward to compensate the influence of heave motion, and finally realized the accurate control of water load. In recent years, lateral anti-swing control has also received a lot of attention. In order to strengthen the swing control of the lifting rope and load, some cranes are equipped with Maryland rigging system, that is, a rope is added in the middle of the lifting rope for traction to reduce the swing of the load. In recent years, many modeling and control methods have been proposed for this kind of marine crane with special mechanism. However, this mechanism greatly limits the working space of the crane system and reduces the mental activity of the original system. Therefore, without changing the mechanical structure of the crane, many studies use various sensors to obtain the motion information of the hull, crane and load, and then design a reasonable swing arm motion controller to suppress the swing of the load during transportation. Among them, Parker and others used command shaping technology to control the pitch and rotation of crane boom, and verified it on a small experimental platform. McKenna et al. modeled the pitching of the boom and the motion of the hull, and suppressed the swing of the load in one direction through the combination of feedforward compensation and feedback control strategy. Masoud et al. adopted the time-delay position feedback control method to reduce the two-dimensional swing angle of the load by manipulating the pitch and rotation of the rotating arm. Sandia National Laboratory designed a control scheme based on multi-sensor information fusion, which compensated the hull motion by controlling the crane motion, and suppressed the load swing well. This method is used in the US Navy T & shy；; Experiments are carried out on ACS system, and good control results are obtained. Subsequently, Schaub and others further improved this control scheme.