多變數系統之閉環路模式識別及其控制相關應用

Closed-Loop Identification of Dynamic Models for Multivariable Systems and Its Control Relevant Applications

林彥佑(Yan-You Lin)

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(2010年)

摘要

通常我們需要的是閉環路識別，但是跟開環路識別比起來更加的困難，因為雜訊與程序輸入之間有關聯。此篇論文針對多變數系統，提出兩個新的閉環路識別方法去解決這個問題，基於一個閉環路，用擬隨機二進制信號(PRBS)去測試。包含程序動態模式和擾動動態模式，這兩種動態模式可以同時識別出來。閉環路系統的有限脈衝響應(FIR)先被識別出來，並且利用有效率的遞迴運算去化簡運算過程，此識別方法是從次空間識別方法衍生出來的，然後利用快速傅立葉轉換(FFT)和快速傅立葉反轉換(IFFT)方法，分別去得到程序動態與擾動動態的頻率響應和FIR模式，而這個運算方法，不需要任何關於模式構造的事先假設。基於這個提出來的方法，控制系統監測與控制器再設計的應用方法因此提出，這些應用在程序模式被識別出來之前就可以完成，可以非常有效的提升控制性能。而模擬出來的結果，證明提出的這個識別方法與應用都是有效的。

關鍵字

閉環路識別 ； 多變數系統 ； 有限脈衝響應 ； 次空間識別方法 ； 控制系統監測 ； 控制器再設計

並列摘要

Closed-loop identification is usually desirable, but more difficult compared to open-loop identification because of the correlation between the noise and the process inputs. This thesis presents two new closed-loop identification methods for multivariable systems to solve this problem. Based on one closed-loop test, the dynamic models, including process and disturbance dynamic models, can be identified simultaneously. The finite impulse responses (FIR) of the closed-loop systems are first estimated by an efficient recursive algorithm derived from subspace identification method. Then, the fast Fourier transform (FFT) and inverse FFT (IFFT) techniques are used to construct the frequency responses and FIR models, respectively, of process and disturbance dynamics. These algorithms do not need prior knowledge of the process or assumption about the model structure. Based on the proposed method, the applications to control system monitoring and controller redesign are thus presented. These applications can be accomplished before the process model being identified, and would be very helpful for improving the control performance. Simulation results have demonstrated the effectiveness of the proposed identification methods and applications.

並列關鍵字

Closed-loop identification ； Multivariable system ； Finite impulse response ； Subspace identification method ； Control system monitoring ； Controller redesign

參考文獻

[1] Ljung, L. System Identification: Theory for the User. Prentice Hall: NJ, 1999.

[2] Forssell, U.; Ljung, L. Closed-Loop Identification Revisited. Automitica 1999, 35, 1215-1241.

[3] Wang, Q. G.; Zhang, Y.; Guo, X. Robust Closed-Loop Identification with Application to Auto-Tuning. J. Process Control 2001, 11, 519-530.

[4] Silva, R.; Sbarbaro, D.; Barra, B. A. L. Closed-Loop Process Identification under PI Control: A Time-Domain Approach. Ind. Eng. Chem. Res. 2006, 45, 4671-4678.

[5] Park, H. I.; Sung, S. W.; Lee, I. B.; Lee, J. On-Line Process Identification Using the Laguerre Series for Automatic Tuning of the Proportional-Integral-Derivative Controller. Ind. Eng. Chem. Res. 1997, 36, 101-111.