A Study of the Controller Tuning for Stabilizing Nonlinear Feedback Systems based on Generalized Models

This paper focusses on the control of nonlinear processes and presents a transformation that approximates a nonlinear model via polynomial expansions. The method helps developing successively more accurate models and also provides a means to quantify the uncertainty associated with the approximation. A stability analysis can be performed in a straightforward fashion to identify stable operating regions as well as stable directions for the output variable moves. Various controller schemes are tested to demonstrate the practicality of the method and a case study of heat-exchanger control is discussed.