Multivariable self-tuning temperature control for plastic injection molding process

This paper develops a multivariable self-tuning control method to improve the performance of the temperature control system for the extruder barrel in the plastic injection molding process. A multivariable mathematical model of the heated barrel is obtained from the energy balance on it. The unknown system parameters in the model are identified by the recursive least square estimation method. The value of the time delay contained in the model is experimentally determined such that the minimum phase model is valid for the plastic intrusion heating process. The multivariable self-tuning control algorithm is constructed for the identified system and is implemented that runs in real-time. Computer simulation and experimental results are illustrated to show the feasibility and effectiveness of the proposed method.