Frequency Domain Analysis of Nonlinear Glucose Simulation Models

Simulation models are frequently used in the development of the artificial pancreas for patients with diabetes. In this paper, frequency domain measurement techniques are used to perform a comparative analysis of widely used nonlinear simulation models of the glucose regulation system in type 1 diabetes. The analysis highlights the main differences between the models under study, based on a nonparametric estimate of their frequency response functions. The underlying linear dynamics, the nature and level of model nonlinearity, and the effect of nonlinear behavior on linear modeling are used as comparison criteria. The analysis shows that, a better understanding of the behavior of such nonlinear systems and the limitations of their linear approximates provides the means to a more careful use in simulations and control design.