Title: Modified Smith predictor with PID structure for control of multivariable processes

Authors: Rames C. Panda, Moses O. Tade

Addresses: Department of Chemical Engineering, CLRI, Adyar, Chennai – 600 020, India. ' Department of Chemical Engineering, Curtin University of Technology, Perth, WA 6845, Australia

Abstract: Industrial processes with dead time, can be controlled using a model-based control strategy called |Smith predictor| (SP) to compensate for the dead time part. Most of the control loops in process industries use PID loops. By introducing a tuning parameter (Ksp) in the control law, to switch between SP and proportional-integral-derivative (PID) modes, an SP with PID (SP-PID) is synthesised in this work to counteract the offset and to obtain a better performance during set-point change as well as load changes. Performance of SP-PID to control linear MIMO systems (square, stable, non-singular linear) are carried-out with decentralised scheme by studying set-point change and load disturbances separately. Present results have been compared with similar existing control strategies. Sensitivity and robustness issues of the present control scheme are also discussed.

Keywords: Smith predictor; dead-time compensator; PID control; MIMO; proportional-integral-derivative; multivariable processes; model-based control; robust control.

DOI: 10.1504/IJPSE.2011.038946

International Journal of Process Systems Engineering, 2011 Vol.1 No.2, pp.197 - 214

Published online: 14 Jan 2015 *

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