In this paper, a closed-loop treatment strategy is proposed for the control of blood glucose levels in type 1 diabetic (T1D) patients. Towards this end, a nonlinear technique for designing suboptimal tracking controllers, called the state dependent Riccati equation (SDRE) tracker, is used based on a mathematical model of the glucose-insulin regulatory system. Since two state variables of the utilized model are not available to the controller, a nonlinear filter is also designed to estimate these variables using the measured blood glucose concentration. Effects of unannounced meals and regular exercise are investigated for a nominal patient and nine diabetic patients with unknown parameters. Numerical simulations are given to show the effectiveness of the proposed treatment strategy even in the presence of parametric uncertainties and the observation noise.
