Model-based control of injection pultrusion process

We address the quality control issues in manufacturing of fiber-resin composites through a prototype process called injection pultrusion. The objective is to maximize production rates while maintaining quality. It is demonstrated that a cascaded control strategy which uses an online process model is suitable in meeting this objective. The strategy uses steady-state cure and pressure models, in conjunction with an optimizer. A first principles model is exercised to generate input data for the feature selection procedures. Based on statistical significance tests, streamlined regression models are generated by identifying processing variables and parameters having a crucial bearing on the part quality and eliminating superfluous variables. Infrequent quality measurements are used to correct for modeling errors. Closed loop control results are presented to demonstrate the successful working of the strategy.