Title: CDM-based two degree of freedom PI controller tuning rules for stable and unstable FOPTD processes and pure integrating processes with time delay

Authors: S. Somasundaram; T. Benjanarasuth

Addresses: Department of Electronics and Instrumentation Engineering, Annamalai University, Annamalai Nagar-608002, Tamilnadu, India ' Department of Instrumentation and Control Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand

Abstract: This work proposes the coefficient diagram method (CDM)-based two degree of freedom proportional integral (CDM-PI) controller tuning rules for stable and unstable first order plus time delay (FOPTD) processes and pure integrating processes with time delay (PIPTD). To derive the tuning rules, a general first order plus time delay (FOPTD) model, the first order Taylor denominator (TD) approximation technique and the pole allocation strategy named CDM is used. The tuning rules derived here are novel and they relate the controller parameters to the process model parameters directly. The performance of the CDM-PI controller utilising the proposed tuning rules is tested with numerical examples of stable, unstable and pure integrating processes with time delay models. The test results indicate that the proposed tuning rules yield promising results over the other PI controllers. Performance measures confirm the effectiveness of the proposed tuning method.

Keywords: CDM-PI; two degree of freedom; tuning rules; process models; performance measures.

DOI: 10.1504/IJAAC.2019.098580

International Journal of Automation and Control, 2019 Vol.13 No.3, pp.263 - 281

Received: 27 Dec 2016
Accepted: 20 Sep 2017
Published online: 28 Mar 2019 *

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