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Two time scale switched systems: An application to steering control in hot strip mills

Abstract : This Ph.D. thesis deals with a certain number of problems arising in practical implementation of control systems: multi time scale phenomena, sudden modifications on the system dynamics, discontinuities on the control signal due to controller switchings, the need of design a limited number of controllers in spite of a wide variation on the physical parameters. In order to illustrate the validity of the obtained results, we resort to a real problem concerning the steel production framework, the robust steering control of a hot strip finishing mill. First, a convex solution of the linear quadratic control design for discrete two time scale systems is proposed. Hence, we address the stability problem of two time scale switched systems. We show that stability of the slow and fast switched subsystems under arbitrary switching rules does not imply the stability of the corresponding two time scale switched system in the singular perturbation form. An additional constraint, independent of the value of the singular parameter and of the switching rule, is provided in terms of linear matrix inequalities. We also introduce a bumpless transfer method for switched systems aiming at reducing the discontinuities on the control signal. Dwell time conditions assessing the asymptotic stability of the closed loop switched system are established. The practical contribution of this thesis, the robust steering control design, exploits most of previous results. The objective is to guarantee the stability of the hot strip mill system and improve the quality of the rolled products.
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Contributor : Ivan Malloci Connect in order to contact the contributor
Submitted on : Monday, December 7, 2009 - 3:44:53 PM
Last modification on : Friday, October 23, 2020 - 8:38:03 AM
Long-term archiving on: : Thursday, June 17, 2010 - 11:25:01 PM


  • HAL Id : tel-00439457, version 1



Ivan Malloci. Two time scale switched systems: An application to steering control in hot strip mills. Engineering Sciences [physics]. Institut National Polytechnique de Lorraine - INPL, 2009. English. ⟨NNT : ⟩. ⟨tel-00439457⟩



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