Avaliação e reprojeto para controle PI de sistemas multivariáveis utilizando estruturas de realimentação com relé.

Abstract

In this work contributions to multivariable decentralized PI control are presented. In the context of SISO systems, simple techniques for open-loop and closedloop first order plus dead time model identification are presented. These techniques use results from relay-based experiments. Furthermore, a procedure for closed-loop evaluation and redesign of PI controllers is presented. In the context of multivariable PI control with decoupling, a procedure to evaluate and redesign simplified decouplers for TITO processes using relay experiments is proposed. The aim of the proposed procedure is to design a simplified dynamic decoupler to be effective at frequencies of interest. This is achieved by first estimating an accurate FOPTD model at those frequencies. An initial simplified decoupler is designed using this model. The initial decoupler is evaluated and redesigned to achieve effective decoupling. For decentralized PI control, a sequential design approach is used. In this regard, a sequential procedure for identification and design is proposed. The procedure uses SISO identification techniques and design methods in a sequential manner to design a decentralized controller. Moreover, a closed-loop experimental robustness evaluation of each loop in a decentralized control structure is proposed. vi