Development of Interval Type-2 Fuzzy Logic Controller for Polymer Extruder Melt Temperature Control
Extrusion is a critical operation in the thermoplastic processing industry since all commercial polymers are compounded. In polymer extrusion, the delivery of a melt which is homogenous in composition and temperature is paramount for achieving high quality extruded products. During the process of extrusion, the quality of the product fluctuates within a certain range due to the variation in the properties of materials, or the operating environment including the system disturbances. This may introduce defects to the end product. A number of control methodologies have been proposed to regulate the product quality in literatures. A simple methodology can be a model-based interval type2 fuzzy logic control (IT2FLC) control linking the output at the die to the input parameter. However, advancements in process control are required to reduce temperature variations across the melt flow which can result in poor product quality. The majority of thermal monitoring methods provides only low accuracy point/bulk melt temperature measurements and cause poor controller performance. Furthermore, the most common conventional Proportional- Integral-Derivative (PID) controllers seem to be incapable of performing well over the nonlinear operating region. This paper presents a model-based interval type-2 fuzzy logic control (IT2FLC) approach to reduce the die melt temperature variations across the melt flow while achieving desired average die melt temperature. Simulation results confirm the efficacy of the proposed controller.
Rama Sarojinee, Vikrant Gupta, Manoj Kumar Jha, M. F. Qureshi