本研究設計並實作一艘使用剛性翼帆的無人自主帆船，旨在建立可應用於迎風航行之導航、控制與調帆系統，由於帆船在迎風航行時會受到無法航行區(In Irons)限制，無法直接朝目標航向前進，因此本研究結合線視距導引法(Line-of-Sight, LOS)與之字形(Z-sailing)換舷航行策略，使載具能在迎風條件下進行路徑追蹤與自主航行，同時，系統利用風向計量測之視風角(Apparent Wind Angle, AWA)作為剛性翼帆角度控制依據，使翼帆維持適當攻角以產生有效升力，進而提供載具前進推力。
本研究之載具平台整合陀螺儀、GPS(Global Positioning System)、磁力計、風速風向計、調帆馬達與磁性編碼器等感測與致動模組，剛性翼帆採用NACA0018對稱翼型設計，並透過調帆馬達調整帆角，以適應不同受風狀態。船體以Rhino軟體進行外型設計，並以聚乳酸（Polylactic Acid, PLA）材料透過3D列印方式製作，後續使用玻璃纖維與樹脂積層強化結構與防水性能。控制系統以Raspberry Pi 5作為主控平台，使用Python撰寫控制程式，並搭配人機介面即時監控載具狀態，同時記錄GPS航跡、視風角、航向誤差、橫向誤差與帆角等實驗資料。
在導航控制方面，本研究採用LOS導引法計算期望航向，使載具逐漸收斂至目標路徑，而非單純使船艏方向與路徑方向一致，控制層則以PID (Proportional-Integral-Derivative)控制器追蹤期望航向，並輸出舵角命令以修正航向誤差，此方法能在風與水流等外部擾動下，透過持續修正期望航向與舵角，使載具維持穩定之路徑追蹤能力，為驗證系統性能，本研究設計多項戶外水域實驗，包括直接航向追蹤與LOS導引追蹤比較實驗、迴旋實驗，以及迎風之字形航行實驗，用以評估載具之航向控制穩定性、路徑追蹤能力、最小轉彎能力與迎風換舷導航性能。
實驗結果顯示，LOS導引法能有效提升載具在戶外水域中的路徑追蹤穩定性，使航向誤差穩定收斂於約10°以內，且航線偏移之平均橫向誤差小於1 m，證明本研究所建立之導航控制系統具備一定之航向修正能力與路徑追蹤精度，在迎風航行實驗中，本研究進一步比較載具與真風方向(True Wind Direction, TWD)呈±45°與±60°夾角時之航行表現，實驗結果顯示，當載具以±45°迎風夾角航行時，視風角較高比例落於迎風航行區域，且所需航行時間較短，路徑推進效率較佳；而±60°迎風夾角因換舷路徑較寬，所需橫向距離較大航行時間較長，視風角分布則較多落於橫風區域，由此可知，在本實驗風場與載具條件下，±45°之字形迎風航行策略具有較佳之整體推進效率。
另外本研究亦比較±45°迎風條件下不同換舷次數對路徑導引效率之影響，實驗結果顯示，換舷一次相較於換舷兩次具有較短航行時間與較高推進效率，但其路徑配置與橫向偏移仍需依實際任務需求進行權衡，整體來說，本研究成功建立一套結合多感測器、LOS導引、PID航向控制與視風角調帆策略之無人自主剛性翼帆船系統，並透過戶外實驗驗證其於迎風航行條件下調帆並自主導航與之字形路徑追蹤能力。

This study designs and implements an autonomous unmanned sailboat equipped with a rigid-wing sail to establish a navigation, heading control, and sail-trim system for upwind sailing. Since sailboats are limited by the In Irons and cannot sail directly toward an upwind target, this study combines the Line-of-Sight(LOS)guidance method with a zigzag tacking strategy to enable autonomous path tracking under upwind sailing. The system also uses the Apparent Wind Angle(AWA)measured by the wind sensor as the basis for sail-trim control, allowing the rigid wing sail to maintain an appropriate angle of attack and generate effective aerodynamic lift for propulsion.
The vehicle platform integrates a gyroscope, GPS, magnetometer, wind speed and direction sensor, sail-trim motor, and magnetic encoder. The rigid wing sail adopts a NACA0018 symmetric airfoil design. The sail angle is adjusted by the sail-trim motor according to different wind conditions. The hull was designed using Rhino and fabricated by 3D printing with Polylactic Acid(PLA), followed by glass fiber and resin lamination to improve structural strength and waterproof performance. A Raspberry Pi 5 is used as the main controller, and the control program is developed in Python. A human-machine interface is used to monitor the vehicle status in real time and record experimental data, including GPS trajectory, heading error, cross-track error, AWA, and sail angle.
For navigation control, the LOS guidance method is used to calculate the desired heading so that the vehicle gradually converges to the target path instead of simply aligning its bow with the path direction. A PID controller then tracks the desired heading and outputs rudder commands to reduce heading error. To verify the system performance, outdoor water experiments were conducted, including direct heading tracking, LOS path-following tests, turning circle tests, and upwind zigzag sailing experiments.
The experimental results show that the LOS guidance method improves path-following stability in outdoor waters. The heading error converged to within approximately 10°, and the average cross-track error was less than 1 m. In the upwind experiments, sailing at ±45° relative to the True Wind Direction(TWD)showed better propulsion efficiency than ±60°, with shorter sailing time and a higher proportion of AWA falling within the upwind sailing region. The comparison of different tack numbers under the ±45° condition also showed that one tack achieved shorter sailing time and higher propulsion efficiency than two tacks. Overall, this study successfully verifies the feasibility of an autonomous rigid-wing sailboat integrating LOS guidance, PID heading control, and AWA-based sail-trim strategy for upwind zigzag path tracking.

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