  A novel approach to design the feedback control based on past states is
proposed for hybrid stochastic differential equations (HSDEs). This new theorem
builds up the connection between the delay feedback control and the control
function without delay terms, which enables one to construct the delay feedback
control using the existing results on stabilities of HSDEs. Methods to find the
upper bound of the length of the time delay are also investigated. Numerical
simulations are presented to demonstrate the new theorem.
