I dug up the actual paper (Cook, 2004) and it turns out the bicycle was symmetrical… and, in fact, entirely virtual.
It’s a plot of a computer simulation, rather than records from a real-world physical experiment.
A bicycle is composed of four rigid bodies: the two wheels, the frame, the front fork (the steering column). Each adjacent pair of parts is connected with a joint that allows rotation along a defined axis, and the wheels are connected to the ground by requiring that their lowest point must have zero height and no horizontal motion (no sliding).
So the simulation has a lot of simplifications from reality, and the picture tells us more about the simulation model than it tells us about the real world. It is a pretty picture, though.
Here’s the paper reference:
Cook, M. 2004. It takes two neurons to ride a bicycle.
(I couldn’t get it from the Cook’s Caltech site, but I found a copy elsewhere.)
The fork is bend so the bike automatically counter-steers against gravity. As long as the speed is high and the wheels are spinning (centripetal/symmetry forces), it will tend to steer in a straight line. So the spinning wheel and the bend, makes the bike run upright. The bend has a name, but I forgot…
I dug up the actual paper (Cook, 2004) and it turns out the bicycle was symmetrical… and, in fact, entirely virtual.
It’s a plot of a computer simulation, rather than records from a real-world physical experiment.
So the simulation has a lot of simplifications from reality, and the picture tells us more about the simulation model than it tells us about the real world. It is a pretty picture, though.
Here’s the paper reference:
Cook, M. 2004. It takes two neurons to ride a bicycle.
(I couldn’t get it from the Cook’s Caltech site, but I found a copy elsewhere.)
The interesting thing in this situation is that it curved at all.
The fork is bend so the bike automatically counter-steers against gravity. As long as the speed is high and the wheels are spinning (centripetal/symmetry forces), it will tend to steer in a straight line. So the spinning wheel and the bend, makes the bike run upright. The bend has a name, but I forgot…