DECOUPLER DESIGN FOR AN INTERACTING TANKS SYSTEM

Abstract

The mathematical model for the two interacting tanks system was derived and the dynamic behavior of this system was studied by introducing a step change in inlet flow rate. In this paper, the analysis of the interaction loops between the controlled variable (liquid level) and manipulated variable (inlet flow rate) was carried out using the relative gain array. Also decoupling technique is applied to eliminate the effect this interaction by design suitable decouplers for the system. The results show that the gain of each loop is cut in half when the opposite loop is closed and the gain of other loop changes sign when the opposite loop is closed. The decoupling method show that the liquid level of tank one is constant when the second inlet flow changes and to keep the liquid level of tank two constant the first inlet flow must be changed.