What is the order of an inverted pendulum system with two degrees of freedom?

[zoom1]

I am considering a simple inverted pendulum system given in the following page;

http://ctms.engin.umich.edu/CTMS/index.php?example=InvertedPendulum&section=SystemModeling

System has two degree of freedom but the control input can be only applied as force to the chart. I am not sure about the order of the system. What is the order of this system ?

Thanks

 

[Hesch]

What is the order of this system ?

I don't quite understand your question: Which part of the system?

The order of a transfer function of a "system" is the highest order of the numerator or denominator. For example (from your link):

has one zero and three poles. Thus the order of the transfer function = 3.