Model free sliding mode controller for blood glucose control: Towards artificial pancreas without need to mathematical model of the system (original) (raw)
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A robust sliding mode controller with internal model for closed-loop artificial pancreas
Medical & Biological Engineering & Computing, 2010
The study presents a robust closed-loop sliding mode controller with internal model for blood glucose control in type-1 diabetes. Type-1 diabetic patients depend on external insulin delivery to keep their blood glucose within near-normal ranges. Closed-loop artificial pancreas is developed to help avoid dangerous, potentially lifethreatening hypoglycemia, as well as to prevent complication-inducing hyperglycemia. The proposed controller is designed using a combination of sliding mode and internal model control techniques. To enhance postprandial performance, a feedforward controller is added to inject insulin bolus. Simulation studies have been performed to test the controller, which revealed that the proposed control strategy is able to control the blood glucose well within the safe limits in the presence of meals and measurements errors. The controller shows acceptable robustness against changes in insulin sensitivity, model-patient mismatch, and errors in estimating meal's contents.
Wiener sliding-mode control for artificial pancreas: A new nonlinear approach to glucose regulation
Computer Methods and Programs in Biomedicine, 2012
Type 1 diabetic patients need insulin therapy to keep their blood glucose close to normal. In this paper an attempt is made to show how nonlinear control-oriented model may be used to improve the performance of closed-loop control of blood glucose in diabetic patients. The nonlinear Wiener model is used as a novel modeling approach to be applied to the glucose control problem. The identified Wiener model is used in the design of a robust nonlinear sliding mode control strategy. Two configurations of the nonlinear controller are tested and compared to a controller designed with a linear model. The controllers are designed in a Smith predictor structure to reduce the effect of system time delay. To improve the meal compensation features, the controllers are provided with a simple feedforward controller to inject an insulin bolus at meal time. Different simulation scenarios have been used to evaluate the proposed controllers. The obtained results show that the new approach outperforms the linear control scheme, and regulates the glucose level within safe limits in the presence of measurement and modeling errors, meal uncertainty and patient variations.
Journal of Research & Health, 2022
Background: Diabetes mellitus (DM) is a common chronic disease with various complications. About 10% of the world’s population suffers from this disease. For smart control of the blood glucose in DM patients, an artificial pancreas was designed and simulated by a predictive sliding mode controller considering the time delay of insulin effect. Methods: In this method, one of the time-delay glucose-insulin models was first selected. Then, using the predictive sliding mode control model, the stability of the blood glucose and insulin concentration was considered as the target. The performance and efficiency of the design were then verified by simulating the parameters of the proposed model in MATLAB software. Results: Using the proposed method, despite considering a 25-minute delay from insulin injection to its effect, the glucose and insulin concentrations reached stability in 60 and 50 minutes, respectively. Conclusion: The results of this study indicate that the combined controller of the predictive sliding mode model control can control blood glucose more effectively than previous controllers and therefore can help reduce disease complications, improve patients’ quality of life, and reduce costs and individual and health systems.