High gain observer design for blood glucose in type I diabetics

Many articles dealing with insulin-glucose control have been published in the last decades, and they mostly assumed that all the system state variables are available for feedback. However, this is not usually the case, or they are not so cheap in practice as blood glucose measurements. In this paper the use of the Nonlinear estimator (also known as the High gain observer) is considered for the three-state minimal Bergman model, as this can be used to reconstruct those state variables that are hard to be recovered directly from the system outputs: remote compartment insulin and plasma insulin deviation. Numerical simulations are included in order to test the behavior and the performance of the proposed observers.