Optimal Setpoint Chasing of Deep Water Semi-Submersible Based on Anchor Chain Reliability

doi:10.19423/j.cnki.31-1561/u.2023.05.097

Abstract

Abstract: The main objective of the motion control of the semi-submersible equipped with mooring-assisted dynamic positioning system is to keep the vessel within a small radius from a target position while preventing the mooring lines from failure. The optimal setpoint chasing algorithm is applied to the semi-submersible equipped with thruster assisted mooring system to ensure the reliability of the mooring lines. The energy consumption equation of the mooring line tension is built according to the structural reliability indexes and dynamic weight coefficients. The optimal setpoint is calculated online by solving the energy consumption equation. The controller is then designed based on the proposed optimal setpoint chasing algorithm, which is verified and compared through time-domain simulations. The results show that with the same control parameters the presented setpoint chasing algorithm can keep the reliability index of the mooring lines at a relatively high level and improve the positioning accuracy while lower the dynamic response amplitude of the mooring line tension. It can promote further engineering applications of the mooring-assisted dynamic positioning system to semi-submersibles.

Key words: mooring-assisted dynamic positioning system, optimal setpoint chasing, structural reliability, semi-submersible, dynamic positioning

摘要： 装备锚泊辅助动力定位系统的半潜平台运动控制主要目标,是将船舶保持在距离目标位置较小的半径内,同时防止系泊缆发生失效。该文将设定点追踪控制方法应用于配备锚泊辅助动力定位系统的半潜平台,以确保系泊缆的可靠性。根据结构可靠度指数和动态权重系数,建立系泊缆张力的能耗方程,通过求解能耗方程在线计算最优设定点;并基于该方法设计了定位系统控制器,通过时域耦合数值模拟对该方法进行验证与对比。结果表明,在控制参数相同的情况下,文中提出的设定点追踪控制方法可以使系泊缆的可靠度指数保持在相对较高的水平,提高定位精度的同时降低系泊缆张力动态响应幅度。该方法将有助于推动锚泊辅助动力定位系统在半潜平台上的进一步工程应用。

关键词: 锚泊辅助动力定位系统, 最优设定点追踪控制, 结构可靠性, 半潜平台, 动力定位

CLC Number:

U675.92

ZHU Xiaomeng, LI Bin. Optimal Setpoint Chasing of Deep Water Semi-Submersible Based on Anchor Chain Reliability[J]. Ship & Boat, 2023, 34(05): 97-105.

朱枭猛, 李彬. 基于锚链可靠性的深水半潜平台设定点追踪控制[J]. 船舶, 2023, 34(05): 97-105.

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