H-infinity controller design for blood glucose regulation in diabetes patients in the presence of uncertain parameters

This paper presents deals with uncertain description of a system for a type I diabetes mellitus patient under an intensive insulin treatment. The control algorithm employs a robust H∞ controller to regulate the blood glucose level in diabetic patients. Diabetes mellitus is a kind of chronic metabolic diseases in which body´s blood glucose regulatory system doesn´t function properly. In this study, Bergman´s minimal model has been used as a base model, to increase the functionalities of the glucose minimal model, some additions could be done. One of the additions is the exercise model and since it is hard to derive exact value of parameters in most biological systems, all parameters of the model has been considered uncertain and therefore parametric uncertainty has been exploited in control design. The control scheme is based on closed-loop feedback strategy. The behavior of the obtained controller was analyzed on ability to track a normoglycemic set point of 81mg/dl in presence of disturbance and course tracking of the closed loop with the nominal system and the system with perturbed parameters. The designed controller proved effective in achieving normoglycaemic and robust to meal and exercise disturbances.