【作者】 金鑫；

【导师】 罗勇；

【作者基本信息】 上海交通大学 ， 船舶与海洋结构物设计制造， 2015， 硕士

【摘要】 动力定位系统在设计过程中,通常只将水平面内的三自由度运动(横荡、纵荡和首摇)作为控制目标,但是对于水线面较小的海洋结构物,例如半潜平台,由推进器推力和波浪联合作用所产生的横摇和纵摇在部分海况下较为明显,对人员的生活和操作以及平台的生产效率和安全都会产生一定的影响。国内外关于半潜平台的五自由度运动控制所开展的研究较少,现有的研究提出了相关的控制模型,但是关于横纵摇运动的机理却少有涉及。因而,本论文将提出一种新的控制策略,本策略在原有的三自由度控制策略的基础上,添加横摇和纵摇的角度、角速度和角加速度作为补充的参考变量。首先,对横纵摇运动加剧的原因进行简单总结,并提出推进器推力使横纵摇运动加剧的四种模式;其次,结合新提出的控制策略,基于现有的内部程序的基础上,对程序进行二次开发,对半潜平台的五自由度运动进行时域模拟,检验该策略的控制效果;最后,将五自由度情况下的定位效果与三自由度情况下的定位效果进行比较,以检验五自由度控制策略对于三自由度定位精度的影响,并且依据时域模拟的结果,对控制策略做出相应的修改和微调。通过对比发现,新提出的五自由度控制策略对于平面三自由度的定位效果影响较小,同时对于横摇和纵摇的抑制较为明显。更多还原

【Abstract】 In dynamic positioning systems for vessels, a three degrees of freedom multivariable controller, which takes the angles and velocities of the horizontal plane motions, surge, sway and yaw into consideration, has always been regarded as adequate for motion control. However, the coupling influences between horizontal plane motions and vertical plane motions of some floating marine constructions may cause large roll and pitch motions, especially for some small-waterplane-area vessels.The research about the 5 degree of freedom motion of the semi-submersible are not very much and some control models have been presented but the detail of the motion theory has not been touched. In this paper, a new controller is proposed. The angles,angular velocities and angular accelerations of the roll and pitch motion are taken into consideration. Firstly, the basic theory of roll and pitch motion of a DP semi-submersible is analyzed. Secondly, the time-domain simulation which use the new controller is done. Thirdly, the positioning effect of the new control law is compared with the effect of the former control law in order to test and optimize the new law. According to the comparing result, it is found that the new control law can limit the maximum amplitude of angle, angular velocity and angular acceleration of the roll and pitch motions without decreasing the positioning accuracy obviously.更多还原