臺灣博碩士論文加值系統

這篇論文主要是探討凌駕控制系統的分析與設計，基於程序安全的考量，我們在一般程序中加入凌駕控制以保護程序。然而，在加入凌駕控制的同時，程序可明顯看出兩個問題：(1)穩定性的問題；(2)切換點與飽和點不匹配的問題。關於穩定性的問題（如：逆響應或時間遲嚴）我門可以改變凌駕控制器的類型（如： 控制或Smith predictor）來解決。對於切換點與飽和點不匹配的問題，我們可以改變主控制器增益（Kc）或是凌駕控制器增益（Kc,or）使主控制器的操作變數達到飽和時隨即啟動凌駕控制。如此一來，便能解決因切換點與飽和點不匹配而造成響應緩慢的問題。
雖然，在設計凌駕控制系統要比一般系統考慮得多，但只要以柔性限制與剛性限制做為系統設計的基本準則並妥善處理可能遭遇的問題，必能使凌駕控制發揮其防護的功能。

The override control provides protective action against abnormal operation and/or incipient process failure. In the hierarchy of instrumentation and control, it is often operated between the soft constraint and the hard constraint and, in terms of control theory, it is a logic-based switching system. It is used throughout process industries and most control loops are patched with some type of override systems. Despite wide-spread applications, little research was done to analyze the override control systems. In this work, the properties of override control are explored. These include switching point, bumpless transfer and steady-state offsets. The stability of the override control is also studied and it is likely that many well-known level override systems may exhibit instability and consequently generates more problem as process approaching constraint. The problem of mismatches between the switching point and saturation in manipulated variable can lead to no control situation for a long period of time. The results clearly indicate that the override control may not be as simple as it appears to be. Methods are proposed to overcome possible stability and mismatch problems. Finally, a procedure is given to for the design of reliable override control system and ensuring inherent safe operation. Simulation results are presented to valid the proposed approach.

第一章緒論 1
第二章凌駕控制系統 5
2.1 背景…………………………………………….. 5
2.2 程序參數與凌駕控制參數…………………. 8
2.2.1 逆響應……………………………………. 11
2.2.2 時間遲延…………….…………………… 14
2.3 結論…………………….…..…………………… 17
第三章凌駕控制系統的分析 30
3.1 切換系統……………………………………….. 30
3.2 塔頂液位凌駕控制….……………………….. 31
3.3 凌駕控制的性質………………………………. 37
3.3.1 切換點…………………………………….. 37
3.3.2 無跳動的轉移(Bumpless Transfer)…. 40
3.3.3 穩態偏差…………………………………. 41
3.3.4 穩定性…………………………………… 42
3.3.5 飽和點和切換點…………………………. 43
第四章凌駕控制的設計 59
4.1 問題及解決方法……………………………….59
4.2 設計步驟…………..…………………………… 62
4.3 實例說明……………………………..……….. 64
第五章 結論 75
參考文獻 77
符號說明 79
附錄A：非線性控制器之穩態偏差 83
作者簡介 92

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