Crossing the seperatrix

[dave1234]

Hi im trying to investigate chaos and a double pendulum. Howvere im stuck for whcih direction to go in. I want to find the point at which the double pendulum shows chaotic behavior. Having read a few peioces here and there, i have an idea that if i could determine when the pendulum crosses a seperatrix then this might be th point im looking for. But where is the seperatrix on a dpouble pendulum? Also im gogin to do this experiment as a practical and am wondering what measurment si can take in order to get some results, of a numerical order, and to plot some graphs, or maybe some phase portraits to show the chaotic behavior.

Any other help on double pendulum investigatons would be helpful.

thanx