Design and analysis of genetic algorithm based controllers for non linear liquid tank system

This paper deals with design of various controllers such as Proportional Integral Derivative (PID) controller, Internal Model Controller(IMC) and transfer function controller by using Genetic Algorithm(GA) for a non-linear liquid conical tank system. Level control of a conical tank is a complex issue because of the nonlinear nature of the tank. For each stable operating point, a First Order Process with Time Delay model was identified using process reaction curve method. The need for improved performance of the process has led to the development of the optimal controllers. GA is an evolutionary algorithm that is proposed in this aspect. The performance of GA based controllers is compared with conventional controllers tuned using Ziegler-Nicholas (Z-N) closed loop method and Z-N open loop method. The comparison is done based on rise time, settling time, overshoot and Integral Time Absolute Error(ITAE) and it was found that the GA based IMC controller is better suited for this process.