Implementation of Online Self-Tuning Fuzzy-PI (STFPI) Controller for Conical Tank System

Abstract

In the chemical process industries, the control of liquid level of a conical tank system is a difficult task due to variation present in cross-sectional area with respect to height. In the proposed research, the conical tank is categorized into three operating regions such as lower, middle, and higher regions. The tuning of PI controller parameters using conventional method is complicated, due to the presence of the inherent nonlinearities in the plant dynamics and various uncertainties, measurement noise. In this research work, the conventional ZNT method has been utilized to tune the PI controller parameters to maintain the liquid level of conical tank system. A model free controller is required and it automatically tunes the PI controller parameters such as proportional gain Kp and integral time Ti, respectively. Hence, a self-tuning fuzzy-PI (STFPI) controller has been proposed. The property of STFPI controller has greater flexible than the conventional controllers and it is also growing very fast because of its simplicity and versatility. In servo operation, the performance of the PI controller is tested in terms of performance indices values such as IAE and ISE.