PID control of glucose concentration in subjects with type 1 diabetes based on a simplified model: An in silico trial

An artificial pancreas system (APS) mimics the function of a real pancreas through monitoring a diabetic´s blood glucose and administering the right dose of insulin via an automatic control loop. It is hailed as a promising cure of diabetes, though this technology is still years away from commercial use due to a few technological bottlenecks. The simulation model of insulin-glucose metabolism of type 1 diabetes mellitus (T1DM) is an essential part of APS. In order to simplify the parameter identification task so that the model can be implemented electronically with ease, this paper presents a simplified model based on Routh approximation model reduction method. The results show that the approximation error between the simplified model and the original model is so small that can be neglected. Based on the simplified model, a PID controller is designed to maintain normoglycemia (90 mg/dl) in subjects with T1DM. The in silico simulation results show that the glucose concentration is controlled well, the risk of hyperglycemia and hypoglycemia is reduced a lot. This suggests that the simplified model describes the insulin-glucose metabolism process accurately, and the PID control algorithm is well-suitable to guide the further development of an APS.