Video: Scientists Build a Riderless Bike That Stays Up On Its Own
Riderless Bike Stays Aloft Sam Rentmeester/FMAX Why does an unmanned bicycle stay upright (for a while) when you give it a shove? Researchers from the United States and the Netherlands designed a riderless bicycle that shows that the various mechanisms scientists have long believed to be responsible for keeping bikes upright are actually not necessary. On a typical bicycle, the front wheel touches ground slightly behind the steering axis (imagine a line extending down from the front forks). This construction is responsible for the "caster effect," in which the bike centers itself not unlike a wheel on a shopping cart. The other effect that was thought to be crucial to bicycle balance is called gyroscopic precession: if a moving bike tilts one way or the other, it will just steer in that direction, thanks to the forward-spinning wheel. Andy Ruina of Cornell University and his team built a scooter-esque bicycle whose front...