Robust Controller Based on an Optimal - Integral Surface for Quadruple-Tank Process

In this paper, a sliding mode control (SMC) based on an optimal-integral sliding surface (SMC-LQI) for quadruple-tank process (QTP) is presented. QTP is multivariable and nonlinear system with strong interactions among its input and output variables. In order to decouple these interactions the Relative Gain Array (RGA) analysis is used. The robust controller and an ideal decoupler are designed from monovariable models obtained by the reaction curve identification method. The performance of the proposed controller is measured using the Integral Absolute Error (IAE) index through simulations by MATLAB®.