Title: Non-linear control of a distillation column coupled with MPC and state observer

Authors: Amiya K. Jana, Saibal Ganguly, Amar Nath Samanta

Addresses: Department of Chemical Engineering, Birla Institute of Technology and Science-Pilani, Rajasthan 333 031, India. ' Department of Chemical Engineering, Indian Institute of Technology-Kharagpur, West Bengal 721 302, India. ' Department of Chemical Engineering, Indian Institute of Technology-Kharagpur, West Bengal 721 302, India

Abstract: The synthesis of multivariable Globally Linearising Control (GLC) structure coupled with non-linear Reduced-Order Observer (ROO) and external linear controller has been studied for a distillation column. Two different linear controllers, namely Dynamic Matrix Controller (DMC) and conventional Proportional Integral (PI) controller, have been used as external controller within the control structure. The proposed control strategies outperformed a dual-loop PI controller. Simulation results of GLC-DMC combined structure indicated better set point tracking performance under modelling uncertainty than GLC-PI control algorithm. The effects of measurement noise on the controller performance also have been investigated through simulation experiment. A new state reconstruction technique, namely Short-cut Process Model-Based Observer (SPMBO), has been developed. The proposed observation scheme provided superior performance under uncertainty over the ROO within the GLC-DMC and GLC-PI control frameworks.

Keywords: distillation column; GLC-DMC; GLC-PI; proportional integral; PI control; reduced-order observers; ROO; short-cut process model-based observer; SPMBO; dynamic matrix control; simulation; process modelling; measurement noise; globally linearising control; nonlinear control; model predictive control; MPC; state observers.

DOI: 10.1504/IJMIC.2007.014621

International Journal of Modelling, Identification and Control, 2007 Vol.2 No.2, pp.88 - 99

Published online: 21 Jul 2007 *

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