Stabilization for a class of delay systems via Z-type control

This paper investigates the Z-type control method to stabilize species populations and make them converge to desired values in a two-species predator-prey model with time delay in the prey species' growth rate. Direct controllers that assume both species' growth rates can be altered through human intervention and indirect controllers that assume only one species' growth can be changed at will are constructed. The Z-type method of construction is theoretically justified, and the potential for certain non-linear activation functions to speed up the control process is highlighted. A general procedure for discretizing state-space systems using the Euler forward formula is described. The discrete versions of the directly and indirectly controlled systems are provided. All Z-type controllers constructed are validated through numerical simulations.