Two degree of freedom controller optimization using GA for shell and tube heat exchanger

Abstract

Design of control system demands optimization of many variables simultaneously, which results in problem of multiobjective optimization. The control degree of freedom is defined as the number of variables that can be controlled in the system. Hence, two-degree-of-freedom (abbreviated as 2DOF) PID control system has advantages over one degree-of-freedom (abbreviated as 1DOF) PID control system. One degree-of-freedom PID controller is used where there are two distinct objectives such as set-point tracking and disturbance rejection. The main objective of 2DOF controller is to control both set point tracking and disturbance rejection simultaneously. The process of heat exchanger which is widely used in process industry having two predominant disturbances one is due to flow variation of input fluid and second is due to temperature variation of input fluid. Hence, heat exchanger is selected as test bench to verify 2DOF control algorithm both for set point tracking and disturbance rejection. Recently, many evolutionary and nature inspired algorithm based controller tuning is attracted researchers due to their advantage to optimize parameters based on cost function, without any knowledge about process. Hence, optimization of 2DOF controller using genetic algorithm, for shell and tube heat exchanger system is proposed. MATLAB is used as software tool to verify 2DOF control strategy for heat exchanger system using genetic algorithm.