Design of IMC-PID Controller Cascaded Filter for Simplified Decoupling Control System

Authors: Le Linh, Truong Nguyen Luan Vu, Le Hieu Giang

Abstract:

In this work, the IMC-PID controller cascaded filter based on Internal Model Control (IMC) scheme is systematically proposed for the simplified decoupling control system. The simplified decoupling is firstly introduced for multivariable processes by using coefficient matching to obtain a stable, proper, and causal simplified decoupler. Accordingly, transfer functions of decoupled apparent processes can be expressed as a set of n equivalent independent processes and then derived as a ratio of the original open-loop transfer function to the diagonal element of the dynamic relative gain array. The IMC-PID controller in series with filter is then directly employed to enhance the overall performance of the decoupling control system while avoiding difficulties arising from properties inherent to simplified decoupling. Some simulation studies are considered to demonstrate the simplicity and effectiveness of the proposed method. Simulations were conducted by tuning various controllers of the multivariate processes with multiple time delays. The results indicate that the proposed method consistently performs well with fast and well-balanced closed-loop time responses.

Keywords: Coefficient matching method, internal model control scheme, PID controller cascaded filter, simplified decoupler.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1125469

References:

[1] E. Gagnon, A. Pomerleau, and A. Desbiens, “Simplified, ideal or inverted decoupling,” ISA Trans., vol. 37, no. 1, pp. 265–276, 1998.
[2] K. Weischedel, T.J. McAvoy, “Feasibility of decoupling in conventional controlled distillation column,” I&EC Fundam, vol. 19, no. 4, pp. 379-384, 1980.
[3] T. J. McAvoy, Interaction Analysis: Principles and Applications. NC, USA: Instrument Society of America, Research Triangle Park, 1983.
[4] F. G. Shinskey, Process Control system: Application, Design and Adjustment. NY, USA: McGraw-Hill, 1988.
[5] D. E. Seborg, T. F. Edgar, and D. A. Mellichamp, Process Dynamics and Control. NY, USA: John Willey & Sons, 1989.
[6] N. L. V, Truong and M. Lee, “Independent design of multi-loop PI/PID controllers for interacting multivariable processes,” J. Process Control, vol. 20, pp. 922-933, 2010.
[7] M. F. Witcher and T. J. McAvoy, “Interacting control systems: steady-state and dynamic measurement of interaction,” ISA Trans, vol. 16, pp. 35-41, 1977.
[8] E. H. Bristol, “Recent results on interactions in multivariable process control,” in Proceedings of the 71st Annual AIChE Meeting, Houston, TX, USA, 1979.
[9] L. S. Tung and T. F. Edgar, “Analysis of control-output interaction in dynamic systems,” AIChE J., vol. 27, pp. 690-693, 1981.
[10] S. Skogestad and I. Poslethwaite, Multivariable Feedback Control. NY, USA: John Wiley and Sons,1996.
[11] M. Morari and E. Zafiriou, Robust Process Control. NJ, USA: Englewood Cliffs, Prentice Hall, 1989.
[12] T. H. Owen and C. S. Orville, Computation Methods in Chemical Engineering. NJ, USA: Prentice Hall PTR, 1996.
[13] S.L. William, Control System Fundamentals. London, UK: CRC Press, 1999.
[14] R. K. Wood and M.W. Berry, “Terminal composition control of binary distillation column,” Chem. Eng. Sci., vol. 28, pp. 1707-1717, 1973.
[15] A. P. Loh, C. C Hang, C. K. Quek, and V. N. Vasnani, “Autotuning of multivariable proportional-integral controllers using relay feedback,” Ind. Eng. Chem. Res., vol. 32, pp. 1002-1007, 1993.
[16] W. L. Luyben, “Simple method for tuning SISO controllers in multivariable systems,” Ind. Eng. Chem. Process Des. Dev., vol. 25, pp. 654-660, 1986.