風帆輔助船舶航行之自動操控研究

THE STUDY ON THE SAIL-ASSISTED SHIP WITH AUTOMATIC STEERING CONTROL

The study investigated the dynamic motion simulation of a sail-assisted ship under service conditions with respect to different wind conditions. Energy-saving effect based on the automatic control was also assessed. The line-of-sight method is used to decide the desired heading angle and then the PD (Proportional-Derivative) controller is applied to manipulate the rudder to maintain the target course. Furthermore, the way of deciding the ideal sail turning-angle based on the aerodynamic characteristic curve is established to get the maximum wind thrust on the ship. The time domain trajectory of the ship motion is simulated by the 4^(th) order Runge-Kutta method. The mathematical model established here is useful for the prelimnary design of the automatic control system of sails on a ship and also helpful to the future application of wind energy on ships. 本論文主要模擬在不同航行狀況與風力方向，使用風帆輔助船舶航行，評估同時對風帆及舵作自動控制之船體反應及節能效果。本文中利用瞄準線方式找出欲保持航向角，並使用PD控制器控制舵角以維持目標航向。根據使用風帆之空氣動力性能曲線，找出理想的轉帆角，得到最大風推力或最小風阻。時程領域之運動反應則以四階Runge-Kutta之數值方法求解。其中，相對風速對輔助推力的影響最為顯著。本文所建立之數學模式對於初步設計風帆之自動控制系統及未來風能利用之技術發展都有相當大的助益。