I'm amazed they got enough power at a reasonable current with 12volts... I think the segway runs like 48 or 96 volts to cut down on current/wiring weight.
Anyone know what motors they used? PWM drives? (Being MIT, they probably put their own FET bridges together)
As a note... i'm not sure you could build this with the current FRC control system... the 120Hz max chop rate on the victors would probably make your servoing relatively rough (Segway probably has an update/chop rate of several KHz)
Amazing project... now if I could just pitch having to build one to my boss so I had the funds....
-q