Abstract
The stability properties of solutions of delay differential systems are investigated for cases when the control inputs are not continuous. The preservation of stability properties when the control input is a sum of impulses gives a more accurate reflection of the real nature of physical systems. Many physical systems such as biological neural nets, blood flows and pulse-frequency-modulated systems exhibit impulsive behaviours. A criterion for ε-invariance realization using impulsed control in systems of delay equations is given.