Design of an Impulsive Offset-Free MHE/ZMPC Scheme For Type 1 Diabetes Treatment

Abstract

Type 1 diabetes treatment can be modeled as an impulsive control system because insulin doses are administered to the patient as small pulses and not as a continuous or discrete input. Therefore, an impulsive scheme of estimation and control is needed. Here, an impulsive MHE is designed and it is coupled with a zone MPC which allows to include the system constraints in both estimation and control problems. In addition, an offset-free strategy is added to compensate the effects of the inherent plant-model mismatch given by the physiological changes of the patient. These variations can generate an inaccurate insulin administration that produces an offset in relation to the nor-moglycemia zone and leads to hypoglycemia or hyperglycemia events. The offset-free MHE/ZMPC formulation reestablishes the normoglycemia behavior by compensating parameter variations. Variations up to 30% were considered, as well as the sensor noise from the continuous glucose monitor.