title: Nonlinear control of a dynamic model of HIV-1.
abstract: Highly active antiretroviral therapy (HAART) reduces the viral burden in human immunodeficiency virus type 1 (HIV-1) infected patients. The paper addresses the problem of controlling the predator-prey like model of the interaction among CD4+ T-cell, CD8+ T-cell, and HIV-1 by an external drug agency. By exploring the dynamic properties of the system, the original system is first regrouped into two subsystems, then a nonlinear global controller is presented by designing two controllers over two complementary zones: a local controller on a finite region and a global controller over its complement. The local controller is designed to guarantee nonnegativty, and avoids the problem of control singularity within the neighborhood of the origin omega. The complementary controller is designed via backstepping for both subsystems over the complementary region. The closed-loop system is globally stable at nominal values through the introduction of a novel bridging virtual control, and the resulting controller is singularity free and guarantees nonnegativity. In this paper, simulations are conducted in discrete-time with sampling time Ts to show the effectiveness of the proposed method.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore. elegesz@nus.edu.sg
authors.forename: Shuzhi Sam
authors.initials: SS
authors.lastname: Ge
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Tian
authors.forename: Tong Heng
authors.initials: TH
authors.lastname: Lee
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy* / Q000821:virology*; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D049109:Cell Proliferation / Q000187:drug effects; D003198:Computer Simulation; D004360:Drug Therapy, Computer-Assisted / Q000379:methods*; D005246:Feedback; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D017711:Nonlinear Dynamics
chemical_list: D019380:Anti-HIV Agents