Dynamic Modeling and Model-Based Control of Exercise Disturbances in Type 1 Diabetic Patients

A mathematical model of the changes in plasma glucose and insulin concentrations during mild-tomoderate physiological exercise was developed for type 1 diabetic patients. From a metabolic prospective, the significant metabolic changes in the body induced by exercise are: increased glucose uptake rate by the working tissues; increased hepatic glucose production to maintain overall glucose homeostasis; and decreased plasma insulin concentration. As a disturbance effect, extended-duration exercise leads to a decrease in hepatic glucose release; the result is an inability to maintain normoglycemia beyond a certain point during prolonged exercise periods. The minimal model developed by Bergman et al. [9] was extended to include the major effects on plasma glucose and insulin levels during and after exercise. Model predictions of glucose and insulin dynamics were consistent with the existing literature data. The exercise model was used in the synthesis of linear and nonlinear MPC algorithms for maintaining normoglycemia during and after mild-to-moderate exercise. The closed-loop result of both the MPCs indicated tight glucose control.