Psyhical Model for Wheelie

[alkalin]

Hi,

I am a student and I have a school project I'm doing on Wheelie.
I need to make an analysis of it and program it, but there are things that I don't understand, especially the psyhical/ mathematical model of the Wheelie on which the control is based.

Is there any place I can get it ? Is it available?
I'm having a hard time understanding exactly how it works just from reading the code. For example, I can't figure out how the filters work, why you substract 'a 1/300 th' of the sensor readings, and what the 'looptime for filters ' are...

Oh, one more question. What would be an appropriate programmer for it?

Any help is welcome.
Thank you.