Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Single Step Response Based Method for the Simple Identification of Wiener-type Nonlinear Process

단일 계단 응답에 근거한 Wiener형 비선형 공정의 간편한 모델 확인 방법

  • Sanghun, Lim (Department of Chemical Engineering, Kyungpook National University) ;
  • Jea Pil, Heo (Department of Chemical Engineering, Kyungpook National University) ;
  • Su Whan, Sung (Department of Chemical Engineering, Kyungpook National University) ;
  • Jietae, Lee (Department of Chemical Engineering, Kyungpook National University) ;
  • Friedrich Y., Lee (LX Hausys America)
  • 임상훈 (경북대학교 화학공학과) ;
  • 허재필 (경북대학교 화학공학과) ;
  • 성수환 (경북대학교 화학공학과) ;
  • 이지태 (경북대학교 화학공학과) ;
  • 이용제
  • Received : 2022.08.06
  • Accepted : 2022.09.30
  • Published : 2023.02.01
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Abstract

The Wiener-type nonlinear model where a static nonlinear block follows a dynamic linear block is widely used to describe the dynamics of chemical processes. A long process excitation step is typically needed to identify this Wiener-type nonlinear model with two blocks. In order to cope with this disadvantage, an identification method for the Wiener-type nonlinear model that uses only a single-step response is proposed here. The proposed method estimates the response of the dynamic linear sub-block from the initial part of the step response, and then the static nonlinear sub-block is identified. Because the only single-step response is used to identify the Wiener-type nonlinear model, there is great benefit in time and cost for obtaining process response. The performance of the proposed identification method with the single-step response is verified through a representative Wiener-type nonlinear process, a pH titration process, and a liquid level system.

동적 선형 블록과 정적 비선형 블록이 직렬로 연결되어 있는 Wiener형 비선형 모델은 여러 화학 공정의 동특성을 묘사하는데 널리 사용되는데, Wiener형 비선형 공정의 모델 확인은 다소 긴 공정 활성화 데이터가 필요하다. 본 연구는 이러한 단점을 보완하기 위하여 단일 계단 응답으로부터 Wiener형 비선형 공정 모델을 찾아낼 수 있는 새로운 모델 확인 방법을 제안한다. 제안된 방법은 계단 응답의 초기 응답으로부터 선형 동적 블록의 예측 응답을 얻어 선형 동적 블록의 모델을 확인하고, 이어서 비선형 정적 블록의 모델을 확인한다. 본 방법은 단일 계단 응답만을 사용하여 공정 모델 확인을 위해 필요한 공정 응답을 얻는 과정에서 시간과 비용적으로 큰 이득을 얻을 수 있다. 제안된 공정 확인 방법의 성능은 대표적인 Wiener형 비선형 공정인 pH 적정 공정과 액위 공정을 대상으로 검증되었다.

Keywords

References

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