Liquid Level Control of Interacting Coupled Spherical Tank System using PI and Fuzzy PI Controller

In process industries there is a high demand for design of multivariable control systems. The goal of this paper is to keep the liquid level in an Interacting Coupled Spherical Tank System (ICSTS) at a constant level. The system's mathematical model is based on fundamental principles such as mass balance and the energy conservation equation. The resulting mathematical model is linearized at an operational point for the design of conventional PI and fuzzy PI controllers. Ziegler–Nichol’s reaction curve tuning method is used to design the linear PI controller and the fuzzy PI controller parameters are obtained by optimizing the cost function using genetic algorithm. Simulation results acquired by conventional linear PI and fuzzy PI controllers are compared and contrasted.