Advanced Hybrid Automated Insulin Delivery System based on Successive Linearization Model Predictive Control: The UniBE System

Abstract

Background and objective: Hybrid automated insulin delivery (hAID) systems represent the most advanced therapy for type 1 diabetes (T1D). Current systems rely on linear or linearized models of glucose homeostasis, which may compromise prediction accuracy and, in turn, timely decision-making by the controller. Physiological variability further complicates insulin requirements, underscoring the need for controllers that adapt dynamically and reduce user burden. Methods: We introduce the University of Bern (UniBE) hAID system, a framework based on successive linearization model predictive control (MPC). The controller integrates basal insulin infusion with the insulin bolus delivery module for meal-related and corrective bolus dosing, adapting bounds in real time to glucose dynamics while accounting for both automated and user-initiated inputs. In-silico evaluation was conducted using the commercial version of the FDA-accepted UVa/Padova metabolic simulator across nine scenarios involving persistent and time-varying errors in meal timing, carbohydrate estimation, and basal insulin profiles. Results: In the baseline scenario, UniBE achieved a mean time in range of 92.0+-13.2%, with time below range at 0.1+-0.2% and time above range at 7.9+-13.2%. Across perturbation scenarios, time in range remained between 75.1 and 92.8%, with low hypoglycemia incidence, demonstrating resilience to clinically relevant disturbances.