Research On Wave Compensation Of Marine Crane Hanging Object

With the exploitation and utilization of humans on marine petroleum resources, as well as the continuous development of marine science and technology on transportation, ship and marine engineering rapidly rise. Since the ship, platform and other marine structures often need to stay on a specific location in the ocean for various operations, such as oceanographic research, oil drilling, salvage rescue and pipeline lay of submarine cables. However, the vessel positioning systems can only position three kinds of marine low-frequency motion, such as sway, surge and yaw, and the operation of crane are restricted by operations water depth, working time, accuracy and other factors, which can’t meet the relevant requirements of marine operations. Thereby it is necessary to reduce the sea conditions’impact on the marine crane, to make the marine crane possess the ability of the heave compensation and the load oscillate suppression, to lift safely and effectively in the bad sea condition, and to improve the performance of the anti-wave marine cranes.In the paper, we select a marine tappet crane as the research subject, and establish the exact nonlinear dynamics model based on the JONSWAP wave spectrum motivation-based model of the ship. Using MATLAB numerical algorithms, we perform the ship crane system dynamics analysis under different sea conditions, and obtain the dynamic response in the different form of operations such as fixed tappet, slewing and luffing movement. And the crane swing pendulum movements are restrained by motors driving boom slewing and luffing control movement, and the heave vertical movement displacements are reduced. By the simplex method optimizing, we get the better ratio control coefficients of slewing, luffing and hoisting motors. Then we substitute the coefficients into the control system and compare with the non-control system. The simulation results show that the swing pendulum movements and the heave displacements are effectively restrained under different sea conditions and different operating process, and the active control of the hanging object is successfully implemented.