System Identification and Design of Inverted Decoupling IMC PID Controller for Non-Minimum Phase Quadruple Tank Process

Abstract

A systematic analytical and experimental method of identification of Two Input Two Output (TITO) Quadruple-Tank Process (QTP), operated at non-minimum phase condition has been presented. Parameters of the process transfer function matrix have been validated on an experimental laboratory-scale physical setup of the process. Appropriate input-output pairing and interaction among control loops have been studied based on the Relative Gain Array (RGA) analysis. Inverted Decoupling Internal Model Control (IMC) based Proportional Integral Derivative (PID) controller has been designed for the TITO process. The effect of changes in controller tuning parameters on the closed-loop response for servo problem has been reported in terms of quantitative performance indices such as Integral of Square of Error (ISE), Integral of Absolute Error (IAE), percentage overshoot and offset. The simulation results have been compared with the literature.

Keywords

• inverted decoupling
• imc-pid controller
• quadruple tank process
• non-minimum phase
• transmission zeros
• rga analysis