Khurram Shahzad*, Iftikhar Ahmad , Yasir Islam
Human Immunodeficiency Virus (HIV) is a lentivirus that badly affects the immune system and becomes the cause of lethal disease called Acquired Immune Deficiency Syndrome (AIDS). This virus mainly destroys the healthy CD4 cells in the immune system and makes it vulnerable to other fatal infections and diseases. Antiretroviral therapy is the most common type of treatment in which we normally use the amount of drug doses to eradicate infected CD4 cells and viral load. In this paper, three nonlinear controllers namely Sliding Mode Controller (SMC), Integral Sliding Mode Controller (ISMC) and Double Integral Sliding Mode Controller (DISMC) have been designed using updated nonlinear mathematical model of HIV/AIDS under the effect of Antiretroviral drug doses. The main purpose of the design of controllers is to destroy the maximum number of infected CD4 cells and viral load while increasing as many healthy CD4 cells as possible. HIV-antigen specific cytotoxic T-lymphocytes play a defensive role together with the drug doses to destroy the number of infected CD4 cells and free viruses in a short time span. Lyapunov based theory has been used to analyze the global stability of the system. The simulations of all three proposed controllers have been done using MATLAB/Simulink and their results have been compared with each other based on the convergence of states to their desired reference values and steady state errors.
