Two Degree of Freedom PID Controller for Quadruple Tank System

Abstract

This work presents an overview of designing and tuning of 2 DOF PI and PID controller for single and two tank interacting as well as non-interacting system. Transfer function of the plant i.e. single tank system and two tank non-interacting as well as interacting system calculated practically, following a mathematical model approach. Conventional PI and PID controller has a limitation when it is tested for set point tracking along with disturbance rejection. We can get a good set point tracking response and good disturbance rejection response separately but difficult to get simultaneously.2 DOF PI and PID controller overcome this disadvantage; it simultaneously provides a good set point tracking as well as good disturbance rejection response. Controller parameters calculated through the Ziegler Nichols’ open loop method. Controller action tested practically on the quadruple tank system using National Instruments’ LabVIEW and compared with the simulation results. Set point and trends of the output variable as well as process variable indicated in the front panel. Data from the tank acquired through the data acquisition card VI microsystem V-01. Level of the liquid in the tank measured by the Rosemount’s level transmitter and output is indicated in the range of 4-20 mA. Process variable is manipulated by the action of control valve.