This may or may not help you but I ran across this (
http://www.geology.smu.edu/~dpa-www/robo/nbot/) a while back and bookmarked it. IIRC somewhere in one of the links I saw at this site was a PDF with a lot of info on an algorithm for balancing. In any case, you might like to check out some of the video clips of the nBot in action. They are pretty neat.