隨著全球海洋資源開發與國防戰略需求的持續提升，自主式水下載具（Autonomous Underwater Vehicle ,AUV）憑藉其無纜化、高機動性及可長時間執行任務等顯著優勢，已廣泛應用於科學觀測與軍事偵察。在載具機構設計上，傳統 AUV多採用十字舵配置，然而近年來X型艉舵（X-rudder）因四個舵面皆能同時參與多自由度控制，具備更高的操縱冗餘度與控制潛力，逐漸成為新一代操舵系統設計的重要趨勢。然而，X型艉舵各舵面之間存在著顯著且強烈的物理耦合效應，任何單一舵面的偏轉都會同時對載具的縱搖、平擺與橫搖產生交叉干擾，大幅增加了姿態控制的複雜度。
為解決此高非線性耦合難題，本研究團隊自行設計並製作一艘具備X型艉舵之自主式水下載具。系統硬體核心採用NI myRIO嵌入式系統，並透過LabVIEW軟體撰寫底層控制程式與人機操作介面；定位與姿態感測系統則深度整合都卜勒測速儀(Doppler Velocity Log, DVL)與深度感測器，以精確擷取載具的三維運動狀態，致動系統為直流馬達和舵板架構。
在控制策略上，本研究以經典 PID 控制理論為核心，配合控制分配（Control Allocation）矩陣，將虛擬控制力矩精準解耦並分配至由直流馬達與舵機構成的推進與操控系統，實現航向穩定、深度控制與橫搖抑制之姿態與舵面協調控制。相關實驗測試於成功大學大型水槽中進行，針對不同航行速度與航線條件，驗證路徑點追蹤與深度控制之穩定性。實驗結果顯示，所建構之控制架構能有效抑制舵面耦合干擾並維持載具姿態穩定，成功完成基本自主航行任務，此實體實驗驗證不僅貼近實際操作情境，更為後續進階控制器設計與實際海洋應用奠定堅實基礎。

With the continuous advancement of global marine resource development and naval strategic demands, Autonomous Underwater Vehicles (AUVs) have been widely deployed in scientific observation and military reconnaissance due to their distinct advantages, including tetherless operation, high maneuverability, and long-endurance mission capabilities. In terms of vehicle mechanical design, traditional AUVs predominantly utilize a cruciform rudder configuration. However, in recent years, the X-rudder configuration has emerged as a significant trend in next-generation steering system design. Because all four control surfaces can simultaneously participate in multi-degree-of-freedom control, the X-rudder offers higher maneuverability redundancy and control potential. Nevertheless, strong and significant physical coupling effects exist among the individual surfaces of the X-rudder. The deflection of any single rudder surface simultaneously exerts cross-interference on the vehicle's pitch, yaw, and roll, drastically increasing the complexity of attitude control.
To address this highly nonlinear coupling challenge, our research team designed and fabricated an autonomous underwater vehicle equipped with an X-rudder configuration. The core hardware of the system utilizes an NI myRIO embedded system, with the underlying control programs and human-machine interface (HMI) developed via LabVIEW software. For the positioning and attitude sensing system, a Doppler Velocity Log (DVL), a six-axis inertial measurement unit (IMU), and a depth sensor are deeply integrated to precisely capture the vehicle's three-dimensional motion states. The actuation system is constructed using DC motors and rudder surface mechanisms.
Regarding the control strategy, this study centers on the classical PID control theory. Combined with a control allocation matrix, the virtual control torques are accurately decoupled and distributed to the propulsion and steering systems composed of the DC motors and servos. This approach achieves coordinated attitude and rudder control for heading stabilization, depth control, and roll suppression. Relevant experimental tests were conducted in the large-scale towing tank at National Cheng Kung University. The stability of waypoint tracking and depth control was verified under various cruising speeds and trajectory conditions. The experimental results demonstrate that the constructed control architecture effectively suppresses rudder coupling interference and maintains vehicle attitude stability, successfully fulfilling basic autonomous navigation missions. This physical experimental validation not only closely aligns with real-world operational scenarios but also lays a solid foundation for subsequent advanced controller design and practical marine applications.

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