Marine cranes are executed in the marine environment in a special crane transport operations, mainly for the transfer of cargo between ship transport, maritime supply, delivery and recovery of important tasks, such as underwater equipment. Special application to offshore marine crane control environment is a big challenge. On the one hand, similar to the land-based cranes of various under-actuated devices, the mobile crane bearing need to control the swing of the load during transport produce to ensure its accuracy and transport efficiency; on the other hand, because of this crane is fixed on the ship and other sports platform, the platform itself Games have a strong impact on the load movement, and in many cases, the load lifting and landing point of the movement and the movement of the crane itself is inconsistent. Specifically, in the course of their work, the crane ship and the ship will receive pitching with the waves, roll and heave, these movements will cause the load to occur swing; especially in the lifting process, easily lead to such movement of the ship has been suspended since the load again collided with the deck, or to have been put down but not yet out of the hook load vacant again, these will threaten the safety of operations. Especially during inter ammunition supply ship, the coupled motion can cause very serious consequences.
Marine crane control is divided into lower hull motion control and suppress the impact of vertical lateral load anti-swing swing two ways. For vertical control, the commonly used agricultural bearings method is to connect the mechanical structure of the crane on board by receiving ship, and the perception of its relative motion, so sling length change and receiving ship heave motion synchronized to the relative movement of the two ships to be compensated, complete landing transport loads on this basis. This method of mechanical structure cranes have special requirements, but also have a greater quality of lifting restrictions. Other scholars lifting equipment for underwater dynamics modeling process, they consider the sling flexibility and hydrodynamic and other factors, and based on the feedback linearization method were designed trajectory tracking and disturbance rejection controller. Feedforward-based synchronization techniques to compensate for the waves heave motion effects, and ultimately into the water on the course load to achieve precise control. In recent years, the lateral anti-sway control has also been a lot of attention. In order to strengthen the sling and the load swing control, on the part of the crane installation Malwith agencies that joined in the middle of the rope sling traction to reduce swinging loads. For marine crane with a special mechanism that, in recent years, made a variety of continuous modeling and control methods. However, such restrictions bodies crane system on a larger working space, reduces the flexibility of the original system. For this reason, many studies without changing the mechanical structure of the crane based on the use of a variety of sensors to obtain the ship, crane, conical bearing the motion information of the load, and to suppress the oscillation of the load during transport through the rational design of arm motion controller. Among them, the use of command shaping technology, the pitching rotation is controlled crane jib, and verified on the pitch and the hull is modeled arm movement, and through the feedforward and feedback control on the part of small-scale experimental platform strategies to inhibit the combination of unilateral load swings upward. Position feedback control using the time lag method, two-dimensional by manipulating pitch and swing arm to reduce the load swing angle. Laboratory design of a control scheme based on multi-sensor data fusion, which by controlling the movement of the crane to compensate for ship motion, to better suppress the swing of the load.
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