Improved Centralized PID Controller with Disturbance Rejection for LTI Multivariable Processes

Abstract

Decoupling control is a notable strategy for MIMO processes to dispose of the impacts of undesirable process interactions. It is a compelling instrument for MIMO process; outer disturbances actually have erase severe impacts on control execution of the closed loop structures. The extended 2-DOF control calculation for the MIMO measures in which the greater part of the controllers to decouple the frameworks first and afterward the controller is intended for the decoupled loops. This eventually builds the intricacy of the system design. This method requires the decoupled PID controller i.e., ‘n’ diagonal controllers for ‘n’ variable processes in addition to two off diagonal lead/lag filters for MIMO processes to achieve the desired performance. But the decoupler requires the exact mathematical model of the processes. If there is any errors occur in the modeling of physical processes, it may not give the satisfactory performance. To overcome these limitations of decoupled control system, a centralized PID controller is proposed. A centralized control system requires, ‘n2’ PID controllers for ‘n’ variable processes will give better response irrespective of model errors. Among these, main diagonal controllers improve the performance and off diagonal reduce the combinability effects of variables in the MIMO processes. The PID controller will be tuned by frequency response approaches to reduce the steady state errors like IAE. The proposed method with disturbance approach in the loop will give improved performance than existing approaches.