基於方塊導向模式與虛擬參考回饋調諧之非線性系統控制器設計方法

Extended VRFT Controller Design Method for Nonlinear Systems Based on Block-Oriented Model Structures

林逸偉(Yi-Wei 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(2014年)

https://doi.org/10.6841/NTUT.2014.00484

摘要

虛擬回饋調諧直接透過一組製程資料即可進行控制器設計，不需要識別程序模式，該方法乃針對線性系統所發展，但由於大部分動態系統都有非線性行為，因此傳統虛擬回饋調諧之實用性有限。本研究基於方塊導向模式，將虛擬回饋調諧延伸至非線性系統之控制器設計，所考慮的方塊導向模式包括Hammerstein、Wiener以及Hammerstein-Wiener非線性結構，而控制系統則是利用線性化控制架構，其中包含靜態非線性之反函數以及線性控制器。本研究利用B-spline函數來代表程序靜態非線性(或其反函數)，根據虛擬回饋調諧概念推導出非線性估計與線性控制器設計之演算法，本方法的優點包含：(1)只需一次性實驗即可進行控制系統設計；(2)線性動態模式識別是不必要的，只需估計靜態非線性；(3)非線性估計及控制器設計在執行上不必進行疊代或非線性最佳化步驟。經由模擬假想和真實非線性系統，本研究控制性能優於傳統虛擬回饋調諧及基於模式之設計方法。

關鍵字

非線性程序控制 ； 虛擬參考回饋調諧 ； Hammerstein模式 ； Wiener模式 ； Hammerstein-Wiener模式 ； B-spline函數

並列摘要

Virtual reference feedback tuning (VRFT) method, originally developed for linear systems, can be used to design the controller by directly using a set of process data without resorting to identification of process models. However, conventional VRFT method has limited practicality because most of the dynamical systems are nonlinear in nature. This work extended the VRFT method to nonlinear systems for nonlinear control system design. In the proposed method, the block-oriented nonlinear models, including Hammerstein, Wiener, and Hammerstein-Wiener structures, are considered for the nonlinear systems. Linearizing control schemes which consist of the inverse of the static nonlinearity and a linear controller is adopted. The B-spline basis functions are used to represent the static nonlinearity (or its inverse). Algorithms for nonlinearity estimation and linear controller design are derived based on the concept of VRFT method. The distinctive features of the proposed method includes: (1) only process data from one-shot experiment are required for control system design; (2) model identification of the linear dynamic subsystem is not required, whereas only the static nonlinearity has to be estimated; (3) nonlinearity estimation and controller design are performed simultaneously without the need of nonlinear optimization and iterative procedures. Simulation examples of hypothetical and real nonlinear systems show that the proposed design method outperforms the conventional VRFT method and model-based design methods.

並列關鍵字

Nonlinear process control ； VRFT ； Hammerstein model ； Wiener model ； Hammerstein-Wiener model ； B-spline function

參考文獻

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