直接由製程資料進行單環路及多環路系統之PID控制器設計

PID Controller Design Directly from Plant Data for Single-Loop and Multi-Loop Systems

曾莞玲(Wan-Ling Tseng)

指導教授 ： 鄭智成

國立臺北科技大學/工程學院/化學工程研究所/碩士(2012年)

摘要

PID控制器是化學程序工業中使用最廣泛的控制器，文獻中也常看到許多基於程序模式(model-based)之PID控制器設計方法的研究。而基於程序模式之PID控制器設計方法主要的缺點就是應用於高階程序動態時，由於不可避免的模式誤差導致控制器效能降低。因此，不需要憑藉程序模式，可以直接以一組程序輸入與輸出數據設計控制器，這個方法是受到高度關注的。
本研究提出以開環測試收集製程資料並直接進行PID控制器的設計，而這個設計方法可視為求解一個模式參考的問題。先針對單環路控制系統進行探討，並將方法延伸至多環路控制系統。單環路系統控制器的設計目標為找到一組PID控制器參數，使其動態行為盡可能的能夠接近所指定的參考模式，以及透過系統韌性的考量選擇參考模式。然而，多環路控制系統可由等效開環程序分成等效單環架構，並以控制器在等效單環系統之動態行為要接近所指定的參考模式為目標進行設計。其中等效單環系統之參考模式則是在主環路之頻寬與交互作用程度的大小之間做合適的選擇，延伸這個最適化方法，並進行探討。模擬結果顯示，基於數據之PID控制器設計方法可以達到與基於模式之控制器設計相當或更好的控制性能。這個控制器設計方法不僅可以解決基於程序模式之控制器設計的缺點，並且具有相當大的實用價值。

關鍵字

PID控制器設計 ； 基於數據調諧 ； 多環路系統 ； 分散型控制 ； 參考模式

並列摘要

PID controllers are the most widely used controllers in the chemical process industries, and various model-based PID design methods can be found in the literature. A major drawback of the model-based PID design is that the effectiveness of these methods would degrade for higher-order process dynamics owing to the inevitable modeling error. Consequently, it is an attractive alternative to design PID controller directly based on a set of process input and output data without resorting to a process model.
This study proposes the PID controller design directly based on process data available from plant test. The PID design for single-loop control systems is first discussed, and then the method is extended to multi-loop control systems. The proposed direct PID controller design approximately solves a model-reference problem. The design goal for single-loop control systems is to obtain PID parameters such that the feedback control system behaves as closely as possible to the prespecified reference model. The robustness consideration is included in the selection of the reference model. Multi-loop control systems can be decomposed into a number of equivalent single loops by an effective open-loop process. Therefore, the design goal for multi-loop control systems is to obtain PID parameters such that each equivalent single loop behaves as closely as possible to the prespecified reference model. The selection of the reference model for each equivalent single loop considers an appropriate tradeoff between the bandwidth of main loop and the magnitude of interaction loops. The optimization problems pertaining to the proposed design are derived, and the associated design issues are addressed. Extensive simulation results show that the proposed data-based PID design gives better or comparable control performance than those attained by the model-based PID designs. Consequently, the proposed design is an attractive alternative to the model-based PID design methods and has considerable potential in practical applications.

並列關鍵字

PID controller design ； Data-based tuning ； Multi-loop system ； Decentralized control ； Reference model

參考文獻

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