Relay Tuning of Multivariable PI Controllers

Abstract A new method for identification of linear multivariable systems using relay feedback is presented. The procedure is a combination of sequential to simultaneous loop closing and relay experiments that are often used for tuning scalar systems. Once the plant transfer matrix is identified at a certain given frequency, Maciejowski technique is used to design multivariable PI controllers. A simulation example is given to illustrate both the identification and design method. Comparative results are shown to demonstrate that the new tuning method has the best set-point response performance. The results can be considered as a significant step towards autotuning of multivariable PI controllers.