Closed-Loop Control of Plasma Osmolality

In this paper, a closed-loop system to regulate plasma osmolality in patients with central diabetes insipidus is investigated. Using model identification techniques, we obtained a 3(rd)-order LTI model of the renal/body fluid system from an 11(th)-order nonlinear system. A Smith Predictor and an H(infinity) controller were developed. The effectiveness of the controller to reject a step disturbance in the plasma osmolality is examined. This paper shows the potential use of control theory in the context of central diabetes insipidus.