Control of the Blood Glucose Level in Diabetic Patient Using Predictive Controller and delay differential equation

Diabetes is known as the sixth leading cause of death in the world leading to kidney and cardiovascular diseases as well. As a result, controlling the disease is of particular importance. To control blood glucose level in diabetes mellitus type I, insulin must be injected into the body. This injection must be strictly controlled – any excessive increase in insulin injection can cause human death. Various controllers have been introduced to control diabetes type I with their own disadvantages. Diabetic patient model used in previous methods is not in compliance with physiological data, uncertainties are not considered in the model, or the controller has a very limited range of stability. In this paper, a Nonlinear Model Predictive Controller is introduced which not only resolves previous problems like lack of consideration of model uncertainty, sharp drop in blood glucose, and low stability, but also specifies insulin injection dosage based on blood glucose level momentarily so that quality of life and decline health care costs [1]. Diabetes is a metabolic disorder in which blood glucose level measures more than normal range of 80 to 140 milligrams per deciliter. In diabetic patients, β cells producing insulin in the body are destroyed and the body cannot control blood glucose levels by itself [2]. So blood sugar needs to be adjusted using insulin injections. In general, control strategies on blood sugar regulation fall into three categories: open loop, semi-closed loop, and closed loop control among which closed loop control is used in this paper.The closed loop control method acts like an artificial pancreas: blood glucose concentration is continuously measured by sensors and after comparing with the desired amount, the required amount of insulin is determined using an appropriate control algorithm, followed by a subcutaneous injection through insulin infusion pump. The overall schema of closed loop glucose control system is shown in Fig. 1.

Keywords:

Diabetes , Insulin- Glucose Regulation System Delays , Blood Glucose Level , Nonlinear Model Predictive Controller