“…When antigens invade the body, the constituent elements of the lymphocyte helper T cell T H , the suppressor T cell T S , and the B cell cooperate with each other for the balance of immune feedback system. Based on the adaptive mechanism of the immune process, the increment PID controller, and the fuzzy control method, the FI-PID controller was designed by taking the number of antigens as error, the total stimulus received by B cells as the control signal or control law [51,52]. Meanwhile, the controller introduces two variables namely the rate of reaction K and the coefficient of stabilizing effect η, and set…”