International audienceThe objective is to design a fully automated glycemia regulation of Type-1 Diabetes (T1D) in both fasting and postprandial phases on a large number of virtual patients. A model-free intelligent PID (iPID) is used to infuse insulin. The feasibility is tested in silico on two simulators with and without measurement noise. The first simulator is derived from a long-term linear time-invariant model. The controller is also validated on the UVa/Padova metabolic simulator on 10 adults under 25 runs/subject for noise robustness test. It is shown that without measurement noise, iPID mimicked the normal pancreatic secretion: a fast rate occurs immediately after meals; it becomes moderate when glycemia decays and reduces to a steady basal mode during fasting. With the UVa/Padova simulator, the robustness against CGM noise and delays was tested. A higher percentage of time in target was obtained with iPID as compared to standard PID with reduced time spent in hyperglycemia.Two different T1D simulators tests showed that iPID detects meals and reacts faster to meal perturbations as compared to a classic PID. The intelligent part turns the controller to be more aggressive immediately after meals without neglecting safety. Thus, postprandial hyperglycemia is reduced with less late postprandial hypoglycemia. The simple structure iPID is a step for PID like controllers since it combines the classic PID nice properties with new adaptive features
Reducing the seismic effect is important to ensure people's safety and structures to remain operational even after the earthquakes. Therefore, many studies have been carried out in this filed in recent years. In this study three types of sliding mode control are designed to reduce the effect of vibration on buildings during an earthquake. An Active Tuned Mass Damper (ATMD) is used in this study as an actuator to absorb seismic vibration. Classical Sliding Mode Control (SMC), Integral Sliding Mode Control (ISMC) and Integral Sliding Mode Control based on barrier function (ISMCbf) are designed to control the performance of ATMD to reduce structural vibrations under effect of earthquake excitation. The three types of controllers are compared under effect of two types of earthquakes: El Centro 1940 earthquake and Mexico City earthquake. This comparison shows that ISMCbf has many advantages, firstly, it does not require prior knowledge of the bounds of disturbances and uncertainties. Secondly, ISMCbf is chattering free, thus, it does need any type of approximation to avoid chattering phenomenon. Finally, the numerical simulation results showed that the state trajectory is confined within the barrier of the sliding manifold and provided a better performance.
Driving blood glycaemia from hyperglycaemia to euglycaemia as fast as possible while avoiding hypoglycaemia is a major problem for decades for type-1 diabetes and is solved in this study. A control algorithm is designed that guaranties hypoglycaemia avoidance for the first time both from the theory of positive systems point of view and from the most pragmatic clinical practice. The solution consists of a state feedback control law that computes the required hyperglycaemia correction bolus in real-time to safely steer glycaemia to the target. A rigorous proof is given that shows that the control-law respects the positivity of the control and of the glucose concentration error: as a result, no hypoglycaemic episode occurs. The so-called hypo-free strategy control is tested with all the UVA/Padova T1DM simulator patients (i.e. ten adults, ten adolescents, and ten children) during a fasting-night scenario and in a hybrid closed-loop scenario including three meals. The theoretical results are assessed by the simulations on a large cohort of virtual patients and encourage clinical trials.
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