Title: Robust stability analysis of the hot-dip galvanising control system

Authors: Gerardo Romero, Luis Garcia, Irma Perez, Rene Dominguez, Marco A. Panduro, Aldo Mendez

Addresses: Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico. ' Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico. ' Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico. ' Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico. ' Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico. ' Department of Electronics Engineering, UAM Reynosa Rodhe, Universidad Autonoma de Tamaulipas, Reynosa, Tamaulipas, Mexico

Abstract: This paper presents new results to compute the robustness margin of the hot-dip galvanising control system. Compared to previous works on this issue, this paper considers a mathematical model of the plant with two inputs and one output. The inputs are used to regulate the output, which represents the Zinc mass coating of steel strip. To achieve this objective, a multivariable PI controller is used, this controller is tuned applying the well known Ziegler and Nichols method, and then the maximum parametric uncertainty is computed in order to guarantee the stability property of the closed-loop control system. The work bases its results on the value set characterisation for interval plants with uncertain time delay, along with the use of the zero exclusion principle. Both results allow to transform the original robust stability problem into a simple visual inspection of a computer aided built graph.

Keywords: hot-dip galvanising; robust stability; robust stabilisation; time-delay systems; value set; interval plants; PI controllers; galvanising control systems; zinc mass coating; steel strip; visual inspection.

DOI: 10.1504/IJAAC.2007.014021

International Journal of Automation and Control, 2007 Vol.1 No.2/3, pp.220 - 232

Published online: 11 Jun 2007 *

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