I am able to reproduce Pyragas' results from his 1992 paper for the Rössler system operating in the spiral regime (e.g. a=0.2, b=0.2 and c=5.7). However, it has been much harder to find situations where an UPO of that system operating in the funnel regime (e.g. a=0.28, b=0.1 and c=8.5) is stabilized using Pyragas' delay control law. I am able to stabilize period-one UPOs but have not found UPOs with longer periods yet. Has anyone information (references) on this problem?
Thank you in advance.