自航船模之船舶操縱運動實驗研究

Abstract

本研究目的為利用自航船模試驗系統來進行船舶操縱性能試驗，對量測到的數據進行分析，並將台船某相似船型的實船數據透過福勞德數相似縮尺與本試驗結果做比較、探討。本實驗透過程式的撰寫，讓無人自航船模內部以電腦進行模糊邏輯的運算與條件式判別，進行自動航行與操縱，自動完成多種船舶操縱性試驗。 本實驗以一艘3.5米之劍艏貨櫃船模進行了定航向自航試驗、迴旋圈試驗、Z形試驗、慣性試驗與威廉森試驗，依據實驗內容與船舶水動力性能來配置實驗所需設備。所有試驗的步驟皆遵從國際船模試驗水槽會議對船舶操性能試驗的規範來進行，當船模透達到設計船速後才開始執行不同軌跡的船舶操縱性能試驗。 定航向自航試驗透過船模上電腦進行模糊邏輯控制讓船模實現無人操縱的定航向直線自航，可以展示自由航行姿態。其它四種試驗皆透過模糊控制邏輯結合運動軌跡程式的程式進行，迴旋圈試驗觀察船舶整體的轉向能力；Z形試驗測試船舶在設定舵角頻繁轉向的能力；慣性試驗可觀測在無螺旋槳作用下的船舶慣性；威廉森試驗配合模擬人員落水系統能看出是否有回到人員落水位置。 實驗結果顯示，透過使用本研究改良的模糊邏輯控制器，定航向自航試驗航向控制的效果很好且穩定。迴旋圈試驗、Z形試驗、慣性試驗則受尺度效應、慣性及壓載的影響，導致船模的螺槳與舵效比實船大，使船模在轉彎、飄移的速度會比較快，迴旋直徑則會比較小。威廉森試驗則是先透過實驗測試找到合適的打舵時機，便能使船模成功返回人員落水處附近。

The purpose of this study is to use the free running model tests to carry out the ship manoeuvring tests. The tested results were scaled by the Froude similarity law to estimate the maneuverability of a similar full scale ship of CSBC. The comparisons between the test results of free running model and the sea trial of the similar ship were discussed. In this study, the fuzzy logic control algorithm was used to operate the motion of the free running ship model. The courses of different tests were programmed and stored in the control computer of the free running model. Then, the ship model can automatically conduct the various ship maneuverability tests. A 3.5 meter sword-bow container ship model was used to conduct the steady course test, turning circle test, zig-zag test, stopping inertia test and williamson turning test. The equipments required for the different experiment were configured according to the different test. All the test steps were followed the ITTC manoeuvring test procedure and guideline. All the ship model manoeuvring tests were conducted after the ship model reached its design model speed. The steady course test was controlled by fuzzy logic and the free running attitude was recorded. The other four tests were carried out through fuzzy control logic combined with the programmed course procedures. The turning circle test can show the turning ability of the ship. The zig-zag test is to test the ship's turning ability at specific rudder angles. The stopping inertia test shows the inertia of the ship without the propeller thrust. The williamson turning test was conducted with a man overboard simulation system to see whether it will return to the location of a man overboard. The experimental results show that by using the improved fuzzy logic controller in this study, the heading control of the steady course test is pretty good and stable. The turning circle test, the zig-zag test and the stopping inertia test were affected by the scale effect, inertia, and ballast. The propeller and rudder effects of the ship model are greater than that of the full scale ship, so that the speed of the ship model in turning and drifting will be faster, and the turning diameter will be smaller. The williamson turning test is needed to find the right timing for turning the rudder through the experimental test, and then the ship model can be successfully returned to the near location of the man overboard.