Differential geometry control of a polymer reactor

Free radical polymerization of styrene in a continuous stirred tank reactor (CSTR) exhibits highly nonlinear behaviour and requires a good nonlinear control. The linear control theory (optimal control, pole placement, H_∞ methods and popular DMC) has limited performance for nonlinear processes like polymerization reactors. Therefore, the development of a nonlinear controller is highly desirable. Using the global external linearization scheme (differential geometric approach) based on Lie-Algebra, a nonlinear controller was developed to control the polymer reactor temperature for setpoint tracking and disturbance rejections and it was demonstrated to outperform P and PI classical controllers.