船舶自動避碰系統之實驗研究

EXPERIMENTAL STUDY ON THE SHIP AUTONOMOUS COLLISION AVIODANCE SYSTEM

本研究以一艘3.5m船模在台北市大湖公園內水域進行自航試驗，根據船模所需之水動力性能數學模式，配合自航試驗之航儀及操控設備，進行船舶自動避碰系統之實驗研究。船舶自動避碰系統包含三個子系統，分別為偵測系統、避碰決策系統及控制系統。偵測系統連接各儀器設備並透過雷射掃描儀偵測他船之動態資訊，將此動態資訊傳送至避碰決策系統。避碰決策系統透過模糊理論計算於各避碰情況下符合國際海上避碰規則之避碰航向，同時將此航向轉成於每一時刻船舶應達成之航向角速度並傳送至控制系統計算操舵舵角。控制系統分為定航向操縱與變航向操縱兩個部分，定航向操縱於船舶偏離設定航向時藉由模糊理論計算回航時所需之操舵舵角，變航向操縱則透過迴旋圈試驗求得操縱性指數，並透過操縱性指數建置Nomoto一階線性船舶操縱運動方程式，透過此運動方程式可計算出於每一時刻達航向角速度所需之操舵舵角。船模於水域上以固定一航向方式航行，在其航道上設立他船使其發生避碰危機，通過本船上之雷射掃描儀偵測他船之動態資訊並由模糊理論計算解除避碰危機之新航向，本船操舵轉彎至計算的新航向上航行，直到避碰危機解除後再回到最初航行之航向，船模自航實驗可證實本研究發展之系統可應用於船舶自動避碰的實現。

An autonomous collision avoidance system was built and validated by the 3.5 m ship model collision experiments in the Dahu Park, Taipei. The autonomous collision avoidance system consists of three subsystems which are detection system, collision avoid-ance decision-making system and control system. The detection system consists of the various sensors and detects the dynamic information of the target ship by the laser scanner. The dynamic in-formation of the target ship is smoothed by the Kalman one-dimensional model and is transmitted to the decision-making system. The decision-making system makes the collision avoidance decision by the Convention on the International Regulations for Preventing Collisions at Sea with the dynamic information and fuzzy logic theory. The decisions are then transmitted to the control system. The control system has two control logics which are fixed heading and variable heading. The fixed heading logic uses the fuzzy control steering system to calculate the rudder angle to keep the ship sailing in a straight line. The variable heading logic adopts the first-order Nomoto equation of motion model with the coefficients calculated from the ship model turning cycle test. The rudder angle which makes the ship to reach the yaw rate is then determined by the decision-making system. The scenario of the autonomous collision avoidance experiments is to make a target ship driving to an own ship which is sailed along a course and cause a collision crisis. The own ship will turn to the collision avoidance course at the design speed until the collision crisis is averted. After the collision crisis, the own ship will return to its direction of the original course. The own ship can pass the target ship safely and return to the original course from a collision crisis. The autonomous collision avoidance system built in the ship manoeuvring study is successful.