Optimal H<SUB align="right">∞ insulin injection control for blood glucose regulation in IDDM patient using physiological model

Abstract

This paper addresses the design of output feedback H∞ controller to deliver insulin via an implantable micro insulin dispenser for insulin-dependent diabetes mellitus (IDDM) patients. The theory of H-infinity optimal control has the feature of minimising the worst-case gain of an unknown disturbance input. When appropriately modified, the theory can be used to design a ‘switching’ controller that can be applied to insulin injection for blood glucose (BG) regulation in IDDM patient. The ‘switching’ controller is defined by a collection of basic insulin rates and a rule that switches the insulin rates from one value to another. The rule employed an estimation of BG from noisy measurements and the subsequent optimisation of a performance index that involves the solution of a ‘jump’ Riccati differential equation. With an appropriate IDDM patient model, simulation studies have shown that the controller could correct BG deviation using clinically acceptable insulin delivery rates to maintain normoglycaemia.