[Home] [Headlines] [Latest Articles] [Latest Comments] [Post] [Sign-in] [Mail] [Setup] [Help]
Status: Not Logged In; Sign In
|
Science/Tech See other Science/Tech Articles Title: Riderless-Bike Research Could Lead to Better Wheels Get a running start and try pushing your bike without riding it — it’ll stay balanced on its own, at least as long as it maintains a certain amount of speed. This has always been true, but a recently published research paper may debunk long-standing beliefs on why your bike can ride itself. And it may make for better bicycle designs in the future. A group of researchers from the United States and the Netherlands have collaborated to produce the two-mass-skate (TMS) bike, a riderless bicycle prototype that lacks two components commonly believed to contribute to the self-stability of bicycles. Before their results were published in Science magazine on Thursday, popular belief held that the gyroscopic and caster effects were keeping bicycles upright. “Ask any enthusiast you know — bicycle mechanics, professional cyclists, manufacturers — how a bike self-stabilizes,” Jim Papadopoulos, engineering professor at the University of Wisconsin-Stout and co-author of the paper, told Wired.com in an interview. “They’ll tell you the same thing. The front forks and the spin of the front wheel.” The theory of gyroscopic precession holds that when a bike leans to the right or to the left, the spinning front wheel forces the bike to turn into the lean, effectively keeping it upright. Further, the caster effect likens the wheels of bicycles to those on shopping carts. Next time you go to the grocery store, notice how the point of contact for the cart’s wheels are just behind the steering axis, which is the same imaginary line that extends downward from the forks of the bike. That makes wheels on casters self-righting: As soon as they start to tip, they turn into the direction of the fall, straightening themselves out again. To debunk the theory, Papadopoulous and colleagues built a bike that eliminates both effects. The steering axis of their model lies behind the front wheel, canceling out the caster effect. And the addition of wheels situated above the front and back wheels, spinning in the opposite direction of each, counters the effect of gyroscopic precession. They gave it a push and, you guessed it, the bike stayed balanced on its own. The researchers found it has to do with the bike’s higher distribution of mass in the rear versus lower in the front. As the front of the bike will try to fall faster than the rear, the front is forced to steer into the fall and pull the bike out of tipping over. So what does this mean for future bikes? “A lot of nerds like to try building different experimental bikes — recumbent bikes, folding models and the like,” Andy Ruina, professor of mechanical engineering at Cornell University, told Wired.com in an interview. “We don’t know if we can build a better bicycle, but using our calculations can give these nerds new ideas in bike design for the future — potentially creating models that are easier to ride, or easier to feel balanced upon while riding straight.” Does this signal the end of training wheels? Probably not. “Hopefully it will lead to work that is more testable and tested,” Papadopoulous said. “Is there a big product to come because of our findings? Maybe. Understanding can do this, but it’s a preamble — we’re understanding it now.”
Post Comment Private Reply Ignore Thread
|
||
|
[Home]
[Headlines]
[Latest Articles]
[Latest Comments]
[Post]
[Sign-in]
[Mail]
[Setup]
[Help]
|
||