Extrusion process control: modeling, identification, and optimization

Our work has been focused on developing a methodology for process control of bulk deformation—specifically, extrusion. A process model is required for control. We state the difficulties which exist with currently available models. An appropriate decomposition and associated assumptions are introduced which permit a real-time process model to be constructed via spectral approximation to solve the axi-symmetric two-dimensional (2D) transient heat conduction equation with heat generation and loss. This solution, simulation results, and model execution times are provided. We use this model development plus output relationships from previous model development work to develop parameter identification and open-loop control methodologies. These methodologies are motivated by the structure and properties of the developed model. We demonstrate that the parameters and control variables enter into the model equations so that the identification and open-loop optimization problems are tractable. An example with plant trial data is provided.