Centralized inverted decoupling for TITO processes

This paper presents a new approach of centralized control for TITO processes which is based on the structure of inverted decoupling. After defining the general expressions of this methodology, it is indicated how to specify the desired open loop transfer function in order to achieve free offset error and the desired performance (gain margins or phase margins). Then, the case of processes with all their elements as first order plus time delay (FOPTD) systems is studied in more detail because it generates two PI controllers and two derivative compensators with time delay, which can be implemented easily. If the process elements are more complex it is proposed to approximate them to FOPTD systems. The methodology is applied to two simulation examples and a real experimental lab process. Comparisons with other authors show its effectiveness.