Improved double controller scheme

This paper presents a novel improved double controller scheme for time delayed processes. The proposed IDCS has a simple structure to analyse and tune which is based on a disturbance observer to estimate an input disturbance and consequently, eliminate the disturbance rejection deficiency of the double controller scheme proposed by Tian and Gao. The proper trade-off between robustness and disturbance rejection can be obtained by means of only one tuning parameter. Moreover, an analytical study on the tuning parameters is presented. In simulation study the performance of the proposed structure is compared with double controller scheme and predictive PI controller proposed by Hägglund. The results illustrate the advantages of the proposed dead time compensator.