Adaptive Clarke-Gawthrop self-tuning control of blood glucose concentration in patients with Type I diabetes

Abstract

Adaptive Clarke-Gawthrop type of self-tuning controller is used for regulating the blood glucose concentration in Type I diabetic patients. This control algorithm is proposed to be integrated into the automation pumps used by diabetic patients as a replacement for manual insulin injection. The controller is implemented on an educational software, GlucoSim which simulates the glucose-insulin dynamics in Type I diabetic patients with insulin infusion being the manipulated variable. The performance of the controller is investigated by changing some important parameters that should be specified at the beginning of the simulations. These parameters are the initial values of the controller parameters, the covariance matrix P, the setpoint of the blood glucose concentration, the constraint factor, the clamp value of the manipulated variable, the forgetting factor, and the control interval. The simulations are carried out for two cases: when the process and disturbance model parameters are unknown and when they are approximately known. The best performance is obtained when the process model parameters are unknown. The optimum parameter settings found are then as follows: the setpoint of the blood glucose concentration is 100 mg dl-1, the constraint factor is 1.5, the insulin infusion is clamped when it exceeds 50 000 mU min-1, the forgetting factor is 0.5 and the control interval is 5 minutes.