Date of Award


Degree Type



Electrical and Computer Engineering

First Advisor

Gao, Zhiqiang

Subject Headings

Polymers -- Extrusion, Viscosity, Automatic control, Process control, polymer extrusion viscosity control disturbance rejection


The interesting background and history of polymer extrusion are first introduced in this thesis. The complexity of the extrusion process is described, along with sources of disturbances. A literature review of the types of controllers that have been used for viscosity regulation in polymer extrusion is given, including the proportional-integral-derivative (PID) proportional-integral (PI) controllers. Polymer viscosity in extrusion is difficult to model accurately and its regulation is prone to disturbances. Active Disturbance Rejection Control (ADRC) is the right method for addressing the model inaccuracies and facilitates a straightforward solution to accommodate industrial needs with parameters that can be easily tuned by the operator. To do this, first the problem of viscosity regulation has to be reformulated as a disturbance rejection problem. This thesis demonstrates, using a circuit and simulation, an advanced solution. The initial results are encouraging, showing better control than PI