Control Configuration Selection and Controller Design for Multivariable Processes Using Normalized Gain

Authors: R. Hanuma Naik, D. V. Ashok Kumar, K. S. R. Anjaneyulu

Abstract:

Several of the practical industrial control processes are multivariable processes. Due to the relation amid the variables (interaction), delay in the loops, it is very intricate to design a controller directly for these processes. So first, the interaction of the variables is analyzed using Relative Normalized Gain Array (RNGA), which considers the time constant, static gain and delay time of the processes. Based on the effect of RNGA, relative gain array (RGA) and NI, the pair (control configuration) of variables to be controlled by decentralized control is selected. The equivalent transfer function (ETF) of the process model is estimated as first order process with delay using the corresponding elements in the Relative gain array and Relative average residence time array (RARTA) of the processes. Secondly, a decentralized Proportional- Integral (PI) controller is designed for each ETF simply using frequency response specifications. Finally, the performance and robustness of the algorithm is comparing with existing related approaches to validate the effectiveness of the projected algorithm.

Keywords: Decentralized control, interaction, Multivariable processes, relative normalized gain array, relative average residence time array, steady state gain.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1337867

References:

[1] P.Grosdidier, M.Morrari, A computer aided methodology for the design of decentralized controllers, Comput.Chem. Eng. 11(1987), pp: 423-433.
[2] M.S.Chiu, Y.Arkun, “Decentralized control structure selection based on integrity considerations”, Ind.Eng. Chem.Res.29 (1990) 369-373.
[3] E.H. Bristol, “On a new measure of interactions for multivariable process control”, IEEE Transactions on Automatic Control 11 (1966) 133–134.
[4] Naik, R. Hanuma, et al. "Controller for Multivariable Processes Based on Interaction Approach." International Journal of Applied Engineering Research (IJAER) 7.11 (2012).
[5] T.J. McAvoym, Y.Arkun,R.Chen,D.Robinson,P.D.Schnelle, A new approach to defining a dynamic relative gain, Control Eng.Pract.11(2003) 907-914.
[6] Xiong, Qiang, and Wen-Jian Cai. "Effective transfer function method for decentralized control system design of multi-input multi-output processes."Journal of Process Control 16.8 (2006): 773-784.
[7] Xiong, Qiang, Wen-Jian Cai, and Mao-Jun He. "Equivalent transfer function method for PI/PID controller design of MIMO processes." Journal of Process Control 17.8 (2007): 665-673.
[8] M.-J. He, W.-J. Cai, W. Ni, L.-H. Xie, “RNGA based control system configuration for multivariable processes”, J. Process Control 19 (2009) 1036-1042.
[9] Rajapandiyan, C., and M. Chidambaram. "Controller Design for MIMO Processes Based on Simple Decoupled Equivalent Transfer Functions and Simplified Decoupler", Industrial & Engineering Chemistry Research, 2012.
[10] W. H. Ho, T. H Lee, and O. P. Gan, “Tuning of multi-loop PID controllers based on gain and phase margin specifications,” Ind. Eng. Chem. Res., vol. 36, pp. 2231-2238, 1997.
[11] Maghade.DK, Patre BM. Decentralized PI/PID controllers based on gain and phase margin specifications for TITO processes, ISA transactions (2012), 51(4),550-558.
[12] Seborg, D. E.; Edgar, T. F.; Mellichamp, D. A. Process Dynamics and Control, 2nd ed.; John Wiley & Sons Asia Pte. Ltd.: Singapore, 2009.
[13] S. Tavakoli, I. Griffin, P.J. Fleming, Tuning of decentralized PI (PID) controllers for TITO processes, Control Engineering Practice 14 (2006) 1069–1080.
[14] Bequette, B. W. Process Control: Modeling, Design, and Simulation, 1st ed.; Prentice Hall: Upper Saddle River, NJ, 2003.
[15] Chien, I. L.;Huang, H.P.; Yang, J.C. A simple Multiloop tuning method for PID controllers with no proportional kick, Ind.Eng.Chem.Res 1999, 38(4), 1456-1468.
[16] A.P.Loh,V.U.Vasnani, Describing function matrix for multivariable systems and use in Multiloop PI design, Journal of process control 4(1994) 115-120.