Study On Wave Compensation System Of Floating Crane

Floating cranes are the most commonly used ships in ocean engineering. Since pendulations of lifting hook which are induced by the roll of ship in waves directly reduce the efficiency of floating crane, it is especially important to study on wave compensation and find a way to suppress such pendulations. In this paper, two approaches were proposed based on the dynamic analysis of crane model. The first approach called Hook Wave Compensation System (HWCS) was proposed from the point of lifting hook. It used Active Tuned Mass Damper (ATMD) as a major component to suppress oscillations of hook directly. The specific structure, control parameters and algorithm of system were designed firstly. Then numerical simulation was performed to analyze the feasibility of such system. The results showed that HWCS was effective to suppress oscillations and LQR (linear quadratic regulator) algorithm could be adopted. The second approach called Base Wave Compensation System was proposed from the point of the base of crane. It used an automatic leveling system to prevent the motion transmission from deck to crane base. An experimental model with double deck structure was designed; the first deck could imitate wave motion, while the second deck had the function of automatic leveling. It used Programmable logic Controller (PLC) to control proportional valves, so that hydraulic cylinders could finish anti-sway motions. At last, two experiments about roll and roll-pitch compensation were carried out. The results showed that the second deck was keep at a state of sway in±1.5°when the first deck was force to a state of sway in±10°.