Electronic chaos controller

The occasional proportional feedback (OFF) controller introduced by Hunt [1] and used for stabilizing periodic solutions in a number of chaotic circuits and also used in the stabilization of a chaotic laser has the disadvantage that it requires an external synchronizing signal. In this paper, we describe a modified version of Hunt's controller which obviates the need for any external signals. We show how the controller has been used successfully to remove chaos in the chaotic Colpitts oscillator. We also describe some theoretical results on the possibilities for controlling a given chaotic system using the OFF method. We prove that the possibility of stabilization depends on the behavior of the system in the neighborhood of the periodic orbit and not on the dimensionality of the attractor on the Poincare surface. (C) 1997 Elsevier Science Ltd.