码头-缆绳-动力定位船舶耦合系统的时频特性分析

为研究系泊状态下动力定位船舶与码头及缆绳间的耦合作用,采取凝集质量法计算系泊缆索有效张力,设置弹簧阻尼单元用以计算码头碰垫间的非线性反力,应用比例-积分-微分控制系统(PID)进行推力控制。在系泊状态下,以动力定位船舶和无动力定位船舶为研究对象,分析了耦合系统中侧推器对消除因一阶波浪载荷而引起的船舶运动影响的作用;针对动力定位船舶,讨论了码头-缆绳及目标位置两个因素对动力定位船舶的定位能力及侧推器性能的影响。结果表明,在选取合理目标位置的情况下,耦合系统中的侧推器性能及动力定位船舶的定位能力均得到了有效提高。

Time-frequency analysis of wharf-cables-DP vessel coupling system

In order to research the coupling interaction among mooring dynamic positioning vessel, wharf and cables, lumped mass method was used to calculate the effective tension, and nonlinear reaction force of dock fenders was simulated by Link unit in OrcaFlex. The thrust allocation of thrusters was based on PID control system. Under mooring conditions, with the comparison the difference in horizontal degree of freedom motion and cable's effective tension between general vessel and dynamic positioning vessel, the effect of thrusters on eliminating ship movement caused by first order wave loads has been explained. According to the results of mooring DP vessel and DP vessel in the same environment load, the influence of wharf-cable and target position on side thrusters and positioning ability were discussed. The results show that the performance of the side thrusters and vessel's positioning capability can be improved effectively under the reasonable selection of target position.