Control of semicontinuous aluminum casting process

In a semicontinuous casting process, the metal level is controlled by the inflow of liquid metal. The quality of the cast product depends on the accuracy of the mold level control. There is a need for a control strategy giving better results than the fixed parameter controller and simple enough to be implemented on the existing control structure, in order to avoid a complete recommissioning of the mold level control system. This paper describes a methodology for the modeling and control of this process, based on the Kessler-Landau-Voda (KLV) method for the autocalibration of proportional integral derivative (PID) controllers. The implementation on an industrial prototype unit at Pechiney Research Center led to improved closed-loop performances (and subsequently, to quality improvement of the cast product) and better understanding of the technological process itself.