TRACKING UNSTABLE PERIODIC-ORBITS IN A BRONZE RIBBON EXPERIMENT

We demonstrate the tracking of an unstable periodic orbit (UPO) in a bronze ribbon experiment. The stabilization of the UPO at each tracking step is performed via the local control method, a variant of the Ott-Grebogi-Yorke [Phys. Rev. Lett. 64, 1196 (1990)] feedback control method. Starting with feedback control vectors extracted from the analysis of the experimental data at each tracking step, we redetermine the location of the UPO using an adaptive orbit correction that exploits the applied control signal and the actual trajectory of the system. Doing so, the unstable periodic orbit can be tracked into a parameter regime where the chaotic attractor has long ago lost its stability and another periodic orbit has become stable. © 1995 The American Physical Society.