UBC Theses and Dissertations
Control of a virtual low pressure aluminum wheel die casting process Vetter, Richard Anthony
This thesis outlines the development of an advanced control solution, specifically Model Based Predictive Control (MPC), for an aluminum wheel low pressure die casting process. The control solution development was performed offline using a high-fidelity 3- D finite element model as a virtual process on which open and closed loop experiments were performed. The open loop experiments facilitated the development of a reducedorder state-space model to predict the approximate input-output behaviour of the casting process. The implemented MPC controller used this state-space model to regulate die temperatures in the virtual process during simulated disturbance scenarios. Two disturbances typically found in the industrial process were simulated. The first simulated disturbance was a ramping metal temperature that simulated the temperature behaviour of the molten metal in the industrial process. The second disturbance was variations in the length of time the die remained open after the cast wheel was ejected from the dies. These disturbances caused the die temperatures to deviate from their optimal values which in turn resulted in defective wheels if the deviations were large enough. The developed control solution improved the process performance by rejecting the simulated disturbances and maintaining the die temperatures near their optimal values. The regulation of the die temperatures resulted in a reduction in the number of cycles where defective wheels were likely.
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