I'm actually using this for a much larger project- it's a lower-body robotic orthosis (think exoskeleton) that is supposed to be able to dynamically self-balance and require minimal input from the user to operate- in this respect, it is almost autonomous in the way it behaves. It basically facilitates movement of the legs to aid in walking for those with congenital diseases (or simply due to senility/osteoperosis)- as far as I know, this is the first biped orthosis able to self-balance. I know it is a complicated project, but those who know me know that I am prone to such things 
(last year's project was a mind-controlled robotic arm Summary - EEG & Prosthetics http://news.cnet.com/2300-11386_3-10008553-8.html). I am entering it for this year's Science Fair (I am a high school sophomore).
It uses several different controlling procedures to facilitate the gait, including an ANN (using back-propagation learning) to control step movements, an IK calculator to determine joint angles, calculation of ZMP (rzero-moment-point), etc. So you can see how frustrated I was when this little part of the project wasn't working properly! 
It uses incline sensing as well as body velocity, joint torques, operator inertia, etc. to determine optimal foot placement- since we as humans can balance in place without moving the feet.
Wish me luck! It's only a few weeks away... 