改良式部分內模式控制法之設計及在自航器應用

On the Design and Application of Modified Partial Internal Model Control-Based Ship Steering Autopilot

本文針對航向不穩定船舶自航器的設計法進行探討，其中自航器設計採用內模式控制（Internal Model Control, IMC）法，以及依據部份內模式控制（Partial Internal Model Control, PIMC）架構，修正而得之改良式部分內模式控制（Modified Partial Internal Model Control, MPIMC）法兩種方式進行之，並比較其控制性能。一般而言，IMC設計法是一種有效的控制架構，但對於一個不穩定的船舶受控系統，並不能直接使用，必須經過較為複雜的設計程式方可適用。而在此提出之MPIMC設計法，可立即應用於具有一個不穩定極點及一個臨界不穩定極點之航向不穩定船舶受控系統，且其設計方法簡單明瞭。其主要設計概念乃將受控體分解成穩定與不穩定之部分，而僅將穩定部分視為受控體模式，再利用控制器將不穩定之部分予以穩定化。綜觀之，本文提出這MPIMC設計法所得控制器階數較IMC設計法所得之數為低，且對於幹擾之靈敏度亦較低。且經由電腦模擬驗證，兩者均能成功的追蹤所輸入的航向參考訊號，達成航向追蹤任務。 Applications of the Internal Model Control (1MG) and Modified Partial Internal Model Control (MPIMC) methods to the design of ship steering autopilot are examined in this work. The standard IMC approach provides useful insights into the controller design: however it requires modifications when applied to unstable plants. The MPIMC method provides a unified approach that achieves a low-order controller, as compared with the standard IMC approach. Specifically, for the MPIMC, the plant is decomposed into a stable part and an unstable part and the stable part is taken as the internal model while the unstable part is stabilized by the controller. Numerical simulations indicate that both methods achieve satisfactory heading angle tracking performance while the MPIMC approach maintains a lower order controller, less overshoot and lower sensitivity than the standard LMC approach.