A novel perturbation method for the stabilization of unstable intermediate
states of hysteresis loop (i.e. S-shaped curve) is proposed. This method only
needs output signals of the system to construct the perturbation form without
delay-coordinate embedding technique, it is more practical for real-world
systems. Stabilizing and tracking the unstable intermediate branch are
demonstrated through the examples of a bistable laser system and delay feedback
system. All the numerical results are obtained by simulating each of the real
experimential conditions.Comment: 6 pages, REVTEX, 4 ps figure
