Identification and PI controller redesign in symmetrical optimum based design

In this paper a proposal for redesign PI controllers with Symmetrical Optimum (SO) based design is presented. The method uses an integration plus first-order model, identified from two frequency points obtained from combined relay experiment. The proposal for the identification of the used model is also presented. The main idea is to apply a double parameterized SO method to get a controller with stability and robustness aspects. The analysis is performed by simulation examples and experimental results.