Today I worked nearly all day on the servo-control of the Sphero. I wanted to do pseudo-code for the Kalman Filter but I realised that I needed to come up with an design for the servo control.
I tried to understand what the actual Sphero does by reading and re-reading this article : http://www.gosphero.com/blog/page/6/. Apparently they are using quaternions, which are very useful to combine rotations without doing too much computation.
I also think that we need to understand the mechanical part a bit more, I found several interesting articles that deal with it.
I plan on doing a synthesis of my work so I can submit it to the teachers.