Relay based identification of TITO process

Abstract

Loop interaction is an important issue in the identification problem of multi input multi output (MIMO) processes. This paper presents a new approach to identify two input two output (TITO) processes using Relay based identification technique where interaction between the loops can be reduced to a acceptable limit. In the proposed structure two relay are inserted in the feedback loops in parallel with two proportional integral derivative (PID) controllers and operate one by one. A pair of first order transfer function models for the TITO process dynamics is identified using the proposed identification method in presence of strong loop interaction. The interaction between the loops is measured using Integral absolute error (IAE). The method is verified through simulation for two different TITO process.