A method and apparatus for sustaining chaos in a system by using the
natural dynamics of the system to redirect flow towards a chaotic region
along unstable manifolds of basin boundary saddles by utilizing small,
infrequent parameter perturbations. The perturbations are determined based
on the location of an unstable state, which is used as a control
reference. The location of the unstable state, which is unobservable, is
estimated by calculating a theoretical branch connecting the current state
of the system to the target unstable state.
