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Scientists Discover How To Stop Luggage From Toppling On the Race Through the Airport (theguardian.com)
An anonymous reader quotes a report from The Guardian: Scientists have worked out why suitcases tend to to rock violently from one wheel to the other until they overturn on the race through the airport. This most pressing of modern mysteries was taken on by physicists in Paris, who devised a scale model of a two-wheeled suitcase rolling on a treadmill and backed up their observations with a pile of equations and references to holonomic restraints, finite perturbations and the morphing of bifurcation diagrams. Fortunately for non-physicists, the findings can be reduced to simpler terms. For the suitcase to rock it had to hit a bump or be struck in some other manner; the faster the suitcase was being pulled, the more minor the bump needed to set it off. So far, so obvious. But Sylvain Courrech du Pont wanted to know more. Why did a rocking suitcase swerve and make such violent movements that it might eventually topple over? After more treadmill tests and more equations, the answer popped up: because a suitcase's handle pulls from the middle and the wheels are at its sides, the suitcase swerves inwards whenever it tilts up on one wheel. If the rocking overcomes the dampening effect that happens when each wheel touches the ground again, the suitcase will keep on rocking or eventually flip over. In conclusion, the researchers discovered that "when a suitcase starts to rock out of control, the correct response is not to slow down but to pull it faster." The scientists have published their findings in the journal Proceedings of the Royal Society.
Or just get one that has 4 wheels and don't look like a dork
People who tow trailers have known about this for decades.
The handle is also on the same side as the wheels, so when you're pulling it along the weight is above the pivot point between the wheel still on the ground and your hand.
If the handle was on the opposite side from the wheels the weight wouldn't be as high (it would be more in line with your hand and the wheel), so the suitcase would be more stable.
The same physical principal applies to two-wheeled trailers pulled by cars with a hitch.
Have you ever seen someone driving down an interstate, two-wheeled U-Haul or similar trailer in tow behind their Honda Civic? I sure have. I back off, and watch while the driver tries various maneuvers. The trailer will start to swing side-to-side. Then it will start skipping from side-to-side. Then I get bored and pass... two lanes over. Never once has one of them simply decelerated and pulled over to the shoulder.
Simple enough to design shock absorbers for the wheels. A proper shock absorber reduces harmonic effects. On vehicles these devices are remarkably affordable and effective. For luggage they could be very cost effective. A simple friction device with a compressed gas cartridge would do the trick. Feel free to design & patent- I don't need the millions it will bring.
...omphaloskepsis often...
I would think that would get you shot, nowadays.
#DeleteChrome
he only thing preventing this scientific breakthrough was the apparent inability to intersect the community of truckers and physicists despite their relative interdependencies.
There is a huge difference between knowing about something and understanding it. Equations of motion for nontrivial situations can get messy fast, and often beyond a few simple general methods, a lot of cookbook, situation-specific methods are used. Expanding upon those cookbook methods is still useful, and sometimes has applications in other situations.
So what this is telling me is that I need to install coilovers on my suitcase. This way I could adjust the dampening and spring rates to ensure the best response on uneven terrain. I could then even lower it if I wanted, but it's pretty slammed as it is.
Dampening makes something wet. Damping absorbs energy (friction). Unless you're adding moisture to slow down oscillations, you're damping rather than dampening.
dom
So when Captain Kirk showed Uhura his inertial dampener...
After a few years you'll get boringly familiar with journalists misreporting familiar things in lurid terms. Media hacks usually know next to nothing about science - and a good headline is much more desirable than strict accuracy even when they do. Put in perspective: this was an undergraduate research project, such as just about every student who takes a degree will undertake at one point or another. Such things are about getting the students to practice and demonstrate their abilities to investigate a problem, draw useful conclusions and present the results. They MAY break new ground, but that's certainly not a requirement - that's what PhDs are for.
How about buying luggage without wheels, and carry it? I know, what a preposterous concept.
Studies (admittedly from the wheeled-luggage lobby) suggest you can buy luggage with wheels and still carry it.
Happiness in intelligent people is the rarest thing I know.
Ernest Hemingway
Studies (admittedly from the wheeled-luggage lobby) suggest you can buy luggage with wheels and still carry it.
The label 'carry-on' is discriminatory and offensive to the roll-ons. Unfortunately, the deodorant lobby stopped the roll-ons from using that label. I think the carry-ons had something to do with it.