Project Description
The productivity of large industrial plants depends strongly on the interaction among the various control loops. Yet, the tuning of the control loops (whether DD or model-based) very seldom is performed taking explicitly into account the multivariable nature of the problem. The power grid and oil refinery facilities are just two classes of inherently multivariable systems that can benefit largely from the use of control design methodologies that are equally inherently multivariable. Our interaction, previous and current, with these two industries is as a strong motivation for our work in developing new DD multivariable methods.
This topic has been a major focus in our group since its very first works [1, 2, 3, 4], in which Prof. Campestrini has developed a Ziegler-Nichols-like tuning method for multivariable plants. More recently, our MSc student Lydia Chia, supported by undergrad Emerson Boeira, has tested a known multivariable version of the VRFT method, and then improved it. Our PhD student Gustavo Rodrigues has contributed to the theoretical understanding of the model reference approach for multivariable problems and is now working on the application of these concepts to develop more robust and effective multivariable DD methods. The concepts and methodologies we develop are experimentally tested in our lab, which contains plant prototypes with actual industrial equipment and software.
[Bibtex]
@mastersthesis{Campestrini:2006,
author = {L. Campestrini},
title = {Sintonia de controladores {PID} descentralizados baseada no m{\'{e}}todo do ponto cr{\'{i}}tico},
school = {Universidade Federal do Rio Grande do Sul},
year = {2006},
address = {Porto Alegre},
url = {http://hdl.handle.net/10183/17625},
abstract = {PID controllers are widely used in process control, in singlevariable systems as well as in multivariable ones. Yet, many of the controllers found in industry are poorly tuned. One of the simplest tuning method of PID controllers consists in identifying some values which are related to the process characteristics, and simply apply some formulae based on these quantities to determine the parameters of the controllers. Theses quantities are the ultimate gain and the ultimate period of the process, which are directly related to the system stability limit. A very interesting characteristic of this method is that it is easily implemented by an auto-tuning control. Thus, auto-tuning methods of this kind of controllers have been largely used in singlevariable systems, using the relay feedback experiment in order to obtain the ultimate quantities, which are needed to tune the controllers. The relay feedback experiment consists in applying a bang-bang control to the process from which the ultimate quantities are to be identified. This procedure, under some conditions, provides a sustained oscillation in the process? output, from which the ultimate quantities are obtained. Aiming at auto-tuning of PID controllers in multivariable systems, the relay feedback experiment can also be used in order to get the ultimate quantities. Different relay feedback procedures can be applied to multivariable processes, but only one of these can identify the real multivariable ultimate quantities, formally considering the multivariable nature of the process: the decentralized relay feedback (DRF). However, the tuning of the controllers proposed in the literature is based on Ziegler-Nichols like formulae, what seems to be, many times, inappropriate. This work presents a multivariable tuning method of decentralized PID controllers, based on the process? ultimate quantities. This method extends the ultimate point method used in SISO systems to multivariable ones, through multivariable analysis of the problem. The analysis of the ultimate point method used in singlevariable systems shows that a PI or PID controller tuned through formulae based on the process? ultimate quantities will always dislocate the ultimate point to another point in the complex plane, determined by the used formulae. The tuning method proposed in this work dislocates the process? ultimate point of a multivariable process to another point in the complex plane, chosen a priori, modifying the system?s ultimate frequency.}
}![[pdf]](http://www.datadrivencontrol.com/wp-content/plugins/papercite/img/pdf.png)
![[doi]](http://www.datadrivencontrol.com/wp-content/plugins/papercite/img/external.png){kind=small}
L. Campestrini, L. C. Stevanatto Filho, and A. S. Bazanella, “Tuning of Multivariable Decentralized Controllers Through the Ultimate-Point Method,” IEEE Transactions on Control Systems Technology, vol. 17, iss. 6, p. 1270–1281, 2009. [Bibtex]
@article{Campestrini:Stevanatto:Bazanella:2009,
Author = {L. Campestrini and L. C. {Stevanatto Filho} and A. S. Bazanella},
Doi = {10.1109/TCST.2008.2006495},
Issn = {1063--6536},
Journal = {IEEE Transactions on Control Systems Technology},
Number = {6},
Pages = {1270--1281},
Title = {Tuning of Multivariable Decentralized Controllers Through the Ultimate-Point Method},
Volume = {17},
Year = {2009},
Bdsk-Url-1 = {http://dx.doi.org/10.1109/TCST.2008.2006495}}[Bibtex]
@inproceedings{Campestrini:Bazanella:2006,
Address = {San Diego},
Author = {L. Campestrini and A. S. Bazanella},
Booktitle = {IEEE Conference on Decision and Control},
Doi = {10.1109/CDC.2006.377478},
Pages = {1834--1839},
Publisher = {IEEE},
Title = {Tuning of multivariable {PID} controllers through the Ultimate Point Method},
Year = {2006},
Bdsk-Url-1 = {http://dx.doi.org/10.1109/CDC.2006.377478}}[Bibtex]
@inproceedings{Campestrini:Barros:Bazanella:2006,
Address = {Gramado - RS - Brazil},
Author = {L. Campestrini and P.R. Barros and A.S. Bazanella},
Booktitle = {IFAC Symposium on Advance Control of Chemical Processes},
Date-Added = {2016-07-13 19:56:34 +0000},
Date-Modified = {2016-07-13 19:57:06 +0000},
Owner = {adchem06},
Pages = {451--456},
Timestamp = {2011.05.05},
Title = {Auto-tuning of PID controllers for MIMO processes by relay feedback},
Year = {2006}}
