@article {328, title = {Online adjustable linear parameter-varying controller for artificial pancreas systems}, journal = {Biomedical Signal Processing and Control}, volume = {86}, year = {2023}, pages = {105164}, abstract = {

The purpose of this article is to present a non-hybrid fully closed-loop controller for the Artificial Pancreas (AP) problem focused on long-term clinical trials and home-use applications. It includes physical activity (PA) and unannounced meals. The controller is based on a robust gain-scheduled algorithm with a Linear Parameter-Varying (LPV) structure. It takes into account the time-varying dynamics of the problem by adapting itself in real-time according to measured glucose levels, and allows online fine-tuning during tests and periodic evaluations without the need of a controller redesign. The proposed fully parameterized LPV control adds several features to our previous results, accounts for the main perturbations of the AP problem and simplifies its implementation. To help in the parameter fine-tuning, a methodology based on clinical information is proposed. In-silico tests show that the achieved performance is similar or better than our previous Automatic Regulation of Glucose (ARG) algorithm, tested in two clinical trials, with the addition of the features mentioned before.

}, keywords = {Artificial pancreas, Diabetes type 1, insulin-on-board, LPV control}, issn = {1746-8094}, doi = {https://doi.org/10.1016/j.bspc.2023.105164}, url = {https://www.sciencedirect.com/science/article/pii/S1746809423005979}, author = {Bianchi, Fernando D. and S{\'a}nchez-Pe{\~n}a, Ricardo S. and Garelli, Fabricio} } @article {291, title = {Control-Oriented Model with Intra-Patient Variations for an Artificial Pancreas}, journal = {IEEE Journal of Biomedical and Health Informatics}, year = {2020}, pages = {1-1}, abstract = {

In this work, a low-order model designed for glucose regulation in T1DM is obtained from the UVA/Padova metabolic simulator. It captures not only the nonlinear behavior of the glucose-insulin system, but also intra-patient variations related to daily insulin sensitivity (${S_{I}}$) changes. To overcome the large inter-subject variability, the model can also be personalized based on a priori patient information. The structure is amenable for linear parameter varying (LPV) controller design, and represents the dynamics from the subcutaneous insulin input to the subcutaneous glucose output. The efficacy of this model is evaluated in comparison with a previous control-oriented model which in turn is an improvement of previous models. Both models are compared in terms of their open- and closed-loop differences with respect to the UVA/Padova model. The open-loop analysis is computed through the root mean square error (RMSE) between the glucose deviation predicted by the models and the UVA/Padova simulator. In closed-loop, the ν-gap metric is used to measure the distance in terms of closed-loop performance between the two models. The results are promising and some illustrative simulations are presented.

}, keywords = {Artificial pancreas, Control-oriented model, Intra-patient variations, LPV model, type 1 diabetes}, issn = {2168-2208}, doi = {10.1109/JBHI.2020.2969389}, author = {Moscoso-V{\'a}squez, Marcela and Colmegna, Patricio and Rosales, Nicol{\'a}s and Garelli, Fabricio and S{\'a}nchez-Pe{\~n}a, Ricardo} } @article {49, title = {Postprandial blood glucose control using a hybrid adaptive PD controller with insulin-on-board limitation}, journal = {Biomedical Signal Processing and Control}, volume = {8}, year = {2013}, pages = {724 - 732}, abstract = {

Abstract This paper addresses the design of blood glucose control during the postprandial period for Type 1 diabetes patients. An artificial pancreas for ambulatory purposes has to deal with the delays inherent to the subcutaneous route, the carbohydrate intakes, the metabolic changes, the glucose sensor errors and noise, and the insulin pump constraints. A time response typically obtained in closed-loop insulin delivery shows hyperglycemia in the early postprandial period caused by the lag in the insulin absorbtion, followed by hypoglycemia caused by control over-reaction. A hybrid control system is proposed in this paper to overcome these problems. An insulin bolus is administered prior to the meals like in open-loop control, whereas a PD controller is used for robust glucose regulation. The controller gain is progressively increased after the bolus from zero up to its nominal value as function of the insulin on board, so that the PD controller becomes fully operational just when the insulin on board falls below a prescribed value. An excessive accumulation of active insulin is avoided in this way, drastically reducing the risk of hypoglycemia. The controller gain is adapted by means of a variable structure algorithm, allowing a very simple software implementation. The robust performance of the control algorithm is intensively assessed in silico on a cohort of virtual patients under challenging realistic scenarios considering mixed meals, circadian variations, time-varying uncertainties, discrete measurement and actuation, sensor errors and other disturbances.

}, keywords = {Artificial pancreas}, issn = {1746-8094}, doi = {http://dx.doi.org/10.1016/j.bspc.2013.06.008}, url = {http://www.sciencedirect.com/science/article/pii/S1746809413000931}, author = {Le{\'o}n-Vargas, Fabi{\'a}n and Garelli, Fabricio and De Battista, Hern{\'a}n and Veh{\'\i}, Josep} } @article {50, title = {Safety Auxiliary Feedback Element for the Artificial Pancreas in Type 1 Diabetes}, journal = {Biomedical Engineering, IEEE Transactions on}, volume = {60}, year = {2013}, month = {Aug}, pages = {2113-2122}, abstract = {

The artificial pancreas aims at the automatic delivery of insulin for glycemic control in patients with type 1 diabetes, i.e., closed-loop glucose control. One of the challenges of the artificial pancreas is to avoid controller overreaction leading to hypoglycemia, especially in the late postprandial period. In this study, an original proposal based on sliding mode reference conditioning ideas is presented as a way to reduce hypoglycemia events induced by a closed-loop glucose controller. The method is inspired in the intuitive advantages of two-step constrained control algorithms. It acts on the glucose reference sent to the main controller shaping it so as to avoid violating given constraints on the insulin-on-board. Some distinctive features of the proposed strategy are that 1) it provides a safety layer which can be adjusted according to medical criteria; 2) it can be added to closed-loop controllers of any nature; 3) it is robust against sensor failures and overestimated prandial insulin doses; and 4) it can handle nonlinear models. The method is evaluated in silico with the ten adult patients available in the FDA-accepted UVA simulator.

}, keywords = {Absorption, Artificial, artificial organs, Artificial pancreas, Biological, Blood Glucose Self-Monitoring, closed loop systems, closed-loop glucose control, Computer Simulation, Computer-Assisted, Diabetes, Diabetes Mellitus, diseases, drug delivery systems, Drug Therapy, drugs, Equipment Safety, FDA-accepted UVA simulator, feedback, glucose control, glycemic control, Humans, hypoglycemia, insulin, insulin-on-board, medical control systems, Models, Pancreas, Physiological, postprandial period, Proposals, reference conditioning, Robustness, safety, safety auxiliary feedback element, sliding mode (SM), sliding mode reference conditioning, Sugar, two-step constrained control algorithms, Type 1, type 1 diabetes}, issn = {0018-9294}, doi = {10.1109/TBME.2013.2247602}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6463437}, author = {Revert, Ana and Garelli, Fabricio and Pic{\'o}, Jes{\'u}s and De Battista, Hern{\'a}n and Rossetti, Paolo and Veh{\'\i}, Josep and Bondia, Jorge} }