Application of modern control and modeling techniques to extrusion processes

Extrusion uses compression to deform a material through a die, creating an arbitrary shape. This process is qualitative, nonstationary, and nonlinear. The operator indirectly controls the process by set-point or direct adjustment of ram speed. Thus, industrial extrusion process control is a rich problem domain for control system engineers. We describe our work on aluminum extrusion. Our problem decomposition is presented. The conventional process control practices and analyses, primarily static, are reviewed. A process model with local material response is required for control. An extension of Kiuchi's model (1986), based on upper bound analysis, is developed. Numerical and experimental simulation results are presented. Two control problems are formulated and developed based on this local perspective.