NXT based Bicycle Robot
I was wondering too myself a few weeks ago if anyone had moved on from the NXT Segway to a "Self-Balancing-Bike" or even a Unicycle. Mechanically and Electronically I thought it would be relatively easy to build, but programming would be a lot more of a challenge.
Low and behold it's been done by Joep Mutsaerts, with his NXTbike-GS (self-balancing bike robot by steer-into-fall)!
The proof came in the form of the following NXT-Bike Video. The LEGO Mindstorms NXT based bicycle robot uses lateral stability control using the concept of "steering into the undesired fall". To my absolute surprise, there is apparently only one line of code used in the controller:
LEGO NXT Bicycle Bot
The NXT based bicycle robot was an assignment for the TUDelft 3mE/PME course Mechatronic System Design II at Delft University. The NXT Bike has a gyro sensor and is powered by nxtOSEK, and uses the same control environment as in NXTway-GS and the concept of steer-into-the fall.
It was Built and programmed by JTM Mutsaerts at Delft University of Technology, Bicycle Dynamics Lab. Download Matlab / Simulink Files: http://www.mathworks.com/matlabcentral/fileexchange/27694.