航行作业船舶考虑舵力的动力定位能力评估方法研究

在船舶动力定位系统中，主推和舵组合（桨舵组合）产生的有效推力矢量区域是非凸的，在进行优化推力分配时需要进行凸化处理。文章提出了一种新的处理办法，将主推和舵的组合等效看成相同位置上的两个不能同时工作的独立推进器，这两个推进器的推力矢量区域都是凸区域，且分别对应主推推力方向不同时的推力矢量区域。在数学上只需通过增加等式约束来实现非凸区域的凸化处理，处理过程更为简单。文中结合具体实例进行了计算。结果对比表明，该方法是可靠有效的。该方法还适用于有多个禁区的推进器处理。

Dynamic position capability evaluation method for marine vessels considering rudder effects

In ship’s dynamic position (DP) systems, the main propeller/rudder pair can produce a thrust vector within a range of directions and magnitudes in horizontal plane for dynamic positioning. The attainable thrust region is non-convex, so some ad hoc treatments should be adopted during the optimal thrust allo-cation process. In this paper, a new method is presented. The main propeller/rudder pair is equivalent to two independent thruster devices, which are located in the same position but never work simultaneously. And the convex vector regions of the new-produced two devices are corresponding to positive or negative thrust of main propeller respectively. Mathematically, a few new constraint equations are added in order to implement convexification of the non-convex thrust regions. The process is much simpler. Based upon this method, DP capability of a real ship is evaluated and compared with results in Kongsberg Co., Ltd, report. Comparisons show that the new method is reliable, and can be applied in the treatments of thrusters with multi-forbidden thrust zones.