The Human Immune System: A Challenging Control Problem

Electrical & Computer Engineering;control;nonlinear;two-stage;time delay;immune system

Vale, Julie

University of Waterloo

关键词: Electrical & Computer Engineering;    control;    nonlinear;    two-stage;    time delay;    immune system;   

Others  :  https://uwspace.uwaterloo.ca/bitstream/10012/858/1/jrvale2004.pdf

瑞士|英语

来源: UWSPACE Waterloo Institutional Repository

【 摘 要 】

This work deals with the control of the human immune system. A standard immune system model is modified byintroducing control signals corresponding to drug cocktail and immune suppressor treatments. The ultimateobjective is to use these control signals to ;;cure;; a chronically-ill patient.Control is challenging forthis system due to nonlinearities and time delays.In fact, it is shown that fundamental aspects of thesystem dynamics are lost when the system is linearised; hence, control approaches involving linearisation arefruitless.Feedback linearisation and some optimal control methods are also investigated and shown to beinfeasible. However, it is shown that, for certain parameter values and initial conditions related to thevirus and patient, a specific open-loop control scheme using only the drug cocktail achieves the objective. Itis also proven that, unfortunately, this control scheme fails for other parameter values and initialconditions.A two-stage open-loop controller that uses both control inputs is then proposed.It is shown insimulation that the two-stage controller works over a larger set of parameters and initial conditions than thesingle-stage controller, but a rigorous analysis of the two-stage controller remains elusive.