Comparing PI controller Performance for Non Linear Process Model

This paper demonstrates the efficient method of tuning PI controller parameters by comparing different tuning rules. The method implies an analytical calculation of the controller gain , Integral time for a PI controlled system which is modeled to be a First Order Plus Dead Time (FOPDT) process. A bench mark non linear system, conical tank is considered for study for which the identified transfer function model to be a FOPTD model. A MATLAB program with an objective is written to find out the optimum value for the PI controller parameter which can achieve the system requirements to minimize the overshoot, to maintain a fast system response, removal of dead time and to maintain robustness. The performance of the controller for different tuning rules has been investigated in a MATLAB simulation environment. Out of these different controllers tuning methods Suyama, Tsang and Rad outperforms well with no overshoot. For setting time Astrom and Hagglund gives better result. This tuning method gives the better results based on performance indices also.