自調式控制應用於樹脂轉注成型

Application of Self-Tuning Control to Resin Transfer Molding

王凱弘(Wang, Kai Hong)

指導教授 ： 姚遠

國立清華大學/工學院/化學工程學系/碩士(2016年)

摘要

樹脂轉注成型(Resin Transfer Molding, RTM)是一種廣泛利用於製造高機械強度與輕質量的高分子複合材料製造技術。其製程是將熱固性樹脂與硬化劑注入封閉模具浸潤預置的纖維補強材，隨後固化成型為成品。
在樹脂轉注程製程中，樹脂流動於纖維補強材中會因為纖維預置物的不規則性排列使樹脂往低滲透係數的區域流動，導致跑道現象(race-tracking)發生與乾班(dry spot)的生成，最終造成產品缺陷。為了提高產品的品質與降低樹脂填充過程中所產生的缺陷，解決的方法之一是透過流動控制使樹脂於填充模具的過程達到預期流動的方式，以此降低產品缺陷的產生。先前文獻指出恆速流動控制可以獲得較好的產品品質。然而，現有樹脂轉注成型流動控制策略通常基於一個不實際的假設，纖維補強材的滲透率是已知的，而且樹脂轉注成型製程系統具有非線性與時變的特性，這對於傳統PID控制器是不適用的。故本文提出應用於樹脂轉注成型之在線流動控制的自調式控制架構，利用最小平方遞迴自適應遺忘因子法(recursive least squares method with an adaptive directional forgetting factor)建立樹脂在線流動控制的數學模型，並基於此系統辨識模型，分別建立藉由Ziegler-Nichols連續圈環法進行控制器參數調整的自調式PI控制器與藉由模具預測控制策略控制流動波前形狀與流動波前速度找出最佳灌注壓力的最佳化控制器。
為了應用本文提出的控制架構對於樹脂轉注成型在線流動控制，實驗模具會分別使用單一灌注口與三個灌注口之模具，且於填充模具的過程中，使樹脂流經低滲透率區域，最終比較傳統PI控制器與本文提出之自調式PI控制器與最佳化控制器於樹脂轉注成型製程中之控制性能。

關鍵字

樹脂轉注成型 ； 流動控制 ； 最小平方遞迴自適應遺忘因子法 ； 模型預測控制策略 ； 自調式PI控制器 ； 最佳化控制器

並列摘要

Resin Transfer Molding (RTM) is a manufacturing technology of polymer composites with high mechanical strength and light weight. Its manufacturing procedure includes injecting liquid thermoset resin and hardener into a closed mold to impregnate fiber reinforced metal placed in advance, together with a curing process.
In RTM, the race-tracking phenomenon often occur during mold filling, which may cause the formation of dry spot and air entrapment. Because of the irregularity in fiber arrangement, the resin flows toward the path with least resistance during the manufacturing process, leading to insufficiently impregnated defects in low permeability zones. One way to improve quality of product and reduce the possibility of generating defects during mold filling is flow control. Previous research indicates that a constant flow velocity is beneficial to good product quality. However, the existing flow control strategies for RTM are often based on an impractical assumption that the permeability of the fiber reinforcement is uniform within the mold and known in advance. The traditional proportional-integral-differential (PID) controller is unsuitable either, because of the time-varying characteristics of the process. To solve these problems, the recursive least squares method with an adaptive directional forgetting factor is adopted in this study to identify the time-varying process model in real time. Then, a self-tuning PI controller is built based on the identified model for constant flow velocity control, whose parameters are adjusted online according to the Ziegler-Nichols continuous cycling method. In addition, a model predictive control (MPC) strategy is also proposed which controls both the shape and velocity of the resin flow front simultaneously.
In order to apply the control structure to on line flow control of RTM, this study adopts mold with single injection gate and three injection gates, let resin flow through low permeability region in model filling, and compares the control performance of tradition PI controller, self-tuning control PI controller and optimizing controller in RTM.

並列關鍵字

resin transfer molding ； flow control ； recursive least squares method with an adaptive directional forgetting factor ； model predictive control strategy ； self-tuning control PI controller ； optimizing controller

參考文獻

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