Hypoglycemia prevention: PID-type controller adaptation for glucose rate limiting in Artificial Pancreas System. Biomedical Signal Processing and Control

NICOLÁS ROSALES; HERNÁN DE BATTISTA; FABRICIO GARELLI

BIOMEDICAL SIGNAL PROCESSING AND CONTROL

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2021

1746-8094

Within the development of closed-loop glucose controllers, one of the major risks isinsulin induced hypoglycemia due to controller overreaction. In this paper, a novelstrategy based on sliding mode control is proposed in order to reduce hypoglycemicevents in glycemic closed-loop control via the subcutaneous route. This is achievedwith the use of a supervisory layer over the main controller, called the GSAFEalgorithm, which is in charge of attenuating excessive glycemic rates of change.When the rate of change of the predicted glycemic level obtained by a Kalman Filterfalls below a certain predefined threshold, the GSAFE layer modulates the output ofthe controller so that the insulin infusion does not cause the glycemic rate of change toexceed a preestablished constraint. In this manner, the insulin delivered is not onlysuspended if it is necessary but it is also adapted by a time-varying gain. In-silico testswith and without the GSAFE layer were run in order to asses the proposalperformance. For a cohort of n=30 subjects the GSAFE layer reduced the time spent inhypoglycemia of a PD type controller in both nominal (0.54 (2.98) vs. 1.81 (3.17),p=0.048) and variability single-day scenarios (0.33 (1.79) vs. 2.23 (5.61), p