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Vol: 48(62) No: 1 / March 2003      

Classical and Modern Multivariable Control Designing Methods of the Three Tank System
L. Kovacs
Department of Control Engineering and Information Technology, Budapest University of Technology and Economics, Faculty of Electrical Engineering and Informatics, H-1117 Budapest, Magyar Tudósok krt. 2, Hungary, phone: (36-1) 463-4027, e-mail: lkovacs@seeger.iit.bme.hu


Keywords: three tank system, decoupling, differential order, disturbance rejection, LQ control, LQR control.

Abstract
In this case study two decoupling and two control methods are realized on the well-known Three Tank System (3TS). One decoupling procedure uses the linearized mathematical model of the system (the P-canonical form), while the other one works directly with the non-linear model and is based on the determination of the differential order. The 3TS control is realized using a classical PI-controller tuned in frequency domain. A second control procedure discusses the disturbance rejection problem in the Hardy H2-space (LQR control, LQ control) [1]. Finally the classical LQ control is compared with the results of the LQR.

References
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[2] S. Skogestad, I. Postlethwaite: \"Multivariable Feedback Control\", Prentice Hall, New Jersey, 2001.
[3] Gatzke E.P., Meadows E.S., Wang Ch., Doyle F.J.: ”Model Based Control of a Four-Tank System”, University of Delaware USA, 2001.
[4] L. Kovács: “Conducerea sistemului cu trei rezervoare (3TS). Studiu de caz. Lucrare de disertaţie, Master thesis”, U.P.T., Timişoara, 2001.
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[9] L. Kovács, Borbély E.: “Three Tank System Control in H2-Space”, SISY 2003 – 1st Serbian-Hungarian Joint Symposium on Intelligent System, Subotica, Serbia-Montenegro, 19-20 Sept. 2003, pp. 267-273.
[10] Şt. Preitl, R.E. Precup, L. Kovacs: “Multi-Tank Systems. Multifunctional Laboratory Didactic Applications”, CONTI 2002, Timisoara, 5th International Conf. on Technical Informatics, Vol. 47 (61), No.1, 2002, pp. 163-166.