This paper analyses the sodium nitroprusside infusion rate control problem that occurs in patients after surgery. The process includes several parameters that can vary over a significant range. Analysis of the model parameters has shown that an internal model controller (IMC) that can meet robust stability and performance criteria can be designed for variations in all of the parameters but one. This model parameter is found from an adaptation law that is introduced in this paper. The resulting controller was shown to meet the robust performance criteria for several simulated patients including some that showed extreme reactions to the drug infusion.
J. Hahn, T. Edison, and T.F. Edgar. "Adaptive IMC Control for Drug Infusion for Biological Systems"
Control Engineering Practice 10, No. 1, pp. 45-56 (2002)