應用迴授控制系統於水處理系統之模組

Abstract

過程控制系統(Process Control System)主要是藉由網路即時地針對控制系統作監控，並期望控制系統可以在中央控制器的控制之下產生最佳的輸出結果。過程控制系統運用的範圍很廣泛，尤其是許多重要的公眾建設，包括了電力系統、水利系統...等等。此篇論文主要是針對水處理系統的控制作討論，水處理系統主要目標是提供穩定且乾淨的使用水給使用者，控制系統期望能夠控制水系統穩定地輸出具有一定品質的使用水。目前一般水處理系統中，大多使用開環式控制(Open-loop Control)，不會針對水系統的輸出作追蹤的動作。另外，開環式控制有時無法應付系統變動性所產生的干擾，並妥善的將這些干擾所造成的影響降至最低。 在此篇論文中，我們建立了一個水系統的模組，模組中考慮了水力的變動性質與水質的變化，並針對此模組作進一步的控制。我們將迴授控制(Feedback Control)應用在水處理系統模組上，藉由追蹤系統輸出的結果，適時的調整控制訊號，使控制系統可以達到我們的期望，並且藉由迴授控制的優點，將外在或系統變動所產生的干擾影響降至 最低。此篇論文使用模型預測控制(Model Predictive Control)來控制水系統，利用模型預測方法的演算方法，預測出系統未來的狀態，並藉由預測出的資訊以及現有系統狀態產生出最佳的控制訊號。藉由我們所提出的模組系統以及所使用的控制方法，期望更詳細且深入的了解水力控制系統，並找出更適合的控制訊號去實際控制水處理系統。

Process control system (PCS) refers to a system with controllers and network connection to monitor and control the physical process. PCSs are usually used in critical infrastructures or industrial plants to control the physical system. Water system providing clean and drinkable water is one of application of PCS. Steady supply and qualified water are appreciate and required to the public. The control goal for water system is to stable the output flow of the system and also maintain the water quality of the outlet. Open-loop control and manual operation to control water system are commonly used now for controlling water system. The outputs of the system is not traced with open-loop control. The disturbance due to the dynamic of the system may be not capable to compensated with open-loop control. In this paper, we proposed a model to simulate the water treatment system. The hydraulic dynamic and the water quality are concerned in this model. Feedback control is utilized to construct the control architecture of PCS. We apply model predictive control (MPC) algorithm to control the system to approach the desired system outputs. With feedback control, controller will trace the output of the system to adjust the control signal real-time. And with MPC, future system states are predicted to assist the controller in generating optimal control signal to meet the requirements. Thus, we can understand more about the behavior of the water system under feedback MPC control with the proposed model.