Suppression of periodic disturbances in continuous casting using an internal model predictor

Fluctuations of the mold level of continuous caster greatly influence the surface quality of the final product. In many plants however periodic disturbances called dynamic bulging occur, which are difficult to suppress because of a substantial input delay. In this work a new measurement is used as disturbance estimate. This signal is then predicted with an internal model observer and applied as disturbance feed forward to the control input. Simulation results with experimental data are presented to show the effectiveness of the approach for mold level control