EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

Lubrication is a key parameter for improving the finishing mill process in hot rolling. The lubrication changes the contact interface between the work rolls and the hot strip. The lubrication can reduce the rolling force, the rolling torque, the energy consumption, the work rolls consumption and the work rolls degradation. Lubrication is also a lever to optimize finishing mill capability. The best way to observe lubrication effect is to analyze the friction variations. Indeed the lubrication reduces the friction coefficient. In this paper, a robust control of lubrication to reduce the roll gap friction in a hot rolling process is proposed. The model obtained from Arcelormittal experimental data is rewritten as a Linear Parameter Varying (LPV) system with delay and saturations. The formulation of the systems contains extended states in order to integrate the delay with a Smith predictor. This delay is compensated by the Smith predictor in an internal loop. The global formulation with the delay and saturations is studied to ensure the process stability against model gain error.