Improved sequential autotuning of PI controllers for industrial-scale polymerization (ISP) reactor

Abstract

Abstract This current work proposes a refined investigation on the improved sequential relay autotuning method to compute the optimal parameters of the decentralized PI controller for Two Input Two Output (TITO) system using relay feedback method. The sustained oscillation occurring in the relay response with the sequential relay autotuning and the simultaneous relay autotuning method is analyzed by taking the higher-order harmonics into consideration and the efficient performance results of the decentralized PI control systems are obtained. These methods have been applied to an Industrial-Scale Polymerization (ISP) reactor transfer function model. In closed-loop studies, comparative analysis of autotuning methods has been carried out using simulation. The effect of measurement noise and robustness are studied in the proposed work. The robustness performance of the system using improved sequential relay autotuning is enhanced by 5–25% for servo operation and 11–40% for regulatory operation. The performance of the systems with the effect of measurement noise using improved sequential relay autotuning is enhanced by 2–24% for servo operation. Comparative analysis has been carried out with the improved sequential relay autotuning and the simultaneous relay autotuning method. It is observed that the proposed method provides improved closed-loop performances and less sum of Integral square error even in presence of robustness and effect of measurement noise.