即時控制系統在小型船舶軌跡控制實驗之應用

Application of Real Time Control Systems to Small Boat Track-Keeping Control Experiments

本研究以小型FRP船舶為載台，整合了航向感測儀及RTKGPS定位資訊等，並利用即時控制軟體作業環境，可將模擬設計控制方塊，直接轉移至控制實體系統之特性，完成了航向保持、路徑點軌跡追蹤等實驗。在控制器設計上採用內模式控制（Internal Model Control, IMC）法則，其具有簡單設計、易於實現等優點。經由電腦模擬找出適當之IMC設計參數可直接應用於實船控制，並獲得理想之控制結果，節省了可觀之實船測試時間。路徑點軌跡追蹤實驗中，則結合了視線導航（Line-of-Sight Guidance）作航向角之計算，經由一系列之航向控制，完成了單點及多點之路徑點（waypoints）軌跡追蹤控制試驗，成功達成任意路徑點軌跡控制之任務。實驗結果顯示暫時之RTK脫鎖後之單機模式，其定位解算約產生二公尺之平移誤差，該誤差對於軌跡追蹤之結果並無明顯影響。而路徑點之間距及路徑點容忍誤差半徑範圍大小值設定，則需配合實驗船之迴旋能力以確保滿意之軌跡追蹤效果。 This work is concerned with the design of an FRP small boat-based tracking system. Specifically, the gyro and the RTKGPS positioning information are integrated under a software environment that allows direct transfer of the simulation-based design blocks to the control of the real boat. The Internal Model Control (IMC) design method characterized by its simplicity in design and easy in implementation is adopted for the controller design. Computer simulations reveal that the IMC design parameter that achieves favorable responses is directly applicable in the real boat-based experiments; hence, considerable time is saved during the experiments. The tracking mission is achieved through a sequence of course-changing control and the reference heading is computed by the line-of-sight (LOS) guidance law. Successful tracking results for up to 12 waypoints are achieved that justify the feasibility of the proposed design and implementation procedures. The experimental results indicate that temporary RTK out of lock causes loss of positioning accuracy which results about 2 meters offset. However this does not prevent the system from completion of the tracking mission and the distance between successive waypoints and the error bound defining reaching the waypoint successfully should be selected according to the turning capability of the boat to ensure satisfactory tracking performance.