After first refusing, OneWheel recalls all of its self-balancing electric skateboards
After first refusing, OneWheel recalls all of its self-balancing electric skateboards
According to the Consumer Product Safety Commission, electric skateboard-maker Future Motion has agreed to recall all of its OneWheels, a...
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ALL of them? As in every single one that they've ever made?
Wow.
Apparently the problem is the way they behave when max speed is achieved.
The thing is, hitting max speed on a self balancer physically means it can no longer balance itself. Balancing out a lean by the user, IS to accelerate. Simply maintaining speed is not enough, to keep a user that is tilted over, on-board, acceleration has to be occurring to offset gravity. If there is no more speed, then that also means there is no more acceleration. If the user is still leaning by this point, gravity wins.
EUCs solve this problem by keeping their electrical actual top speed far above the advertised top speed, and signaling to the user in some way when they ABSOLUTELY MUST STOP accelerating. Because once the hard limit of the voltage coming out of the battery is reached, the self balancing ceases.
OneWheels have pretty small batteries, and much lower top speeds than most EUCs. I'm not surprised a lot of people pushed the limits, and hit them. AFAIK, they don't have an audible signal that warns the user they are approaching max speed, either.
Couldn't they just put like a small wheel on the front that only got used if they dip too far that way it's not a slingshot. Like it's still "one" wheel when it's used normally.
That still leaves the problem that when it hits top speed, the user is leaning forwards.
When the acceleration stops, the physical effect is the same as when you are leaning at that same angle, but standing still. That the board would be able to continue rolling at that same speed, doesn't solve the fact that to get under a leaning rider and to keep them fom hitting the pavement, it needs to accelerate, not just maintain speed.
Going from top acceleration, to no acceleration, is the same as going from no acceleration, to full braking, front wheel or not.
Thanks for this detailed explanation.
These are everywhere in NYC. Last year, a guy who passed me in the bike lane on one of these ate shit for what seemed like no reason a block and a half after he flew by me. I stayed with him until the ambulance arrived and never saw him again, but I always wondered what caused his fall. Now I know.
It's unfortunate. I met a guy who gushed about how amazing his high-performance EUC was. How it cannot fall over because it's gyroscopically stabilized and I had to sit him down for a long talk to explain to him all the limitations of these things. He was under the impression that it had some kind of ABS braking, too, which supposedly made it safe to ride on ice.
They are often advertised to have E-ABS, which is just a marketing term for regenerative braking. It doesn't actually provide the benefits of ABS on motorcycles and cars, which are smart braking systems which rely on traction-sensors from more than one wheel. Real ABS is not possible with just one wheel. And active balancers need 100% traction 100% of the time. They need torque to self-right, and without traction, there is no torque.
Yes, they are amazing, but they aren't nearly magical enough to be stupid-proof. You need to know how they work to really ride them safely.
ABS only needs to sense when the wheel locks up, or stops spinning. You only need one when for that. Traction control usually uses multiple sensors, maybe you're thinking of that?
Except a wheel doesn't need to actually lock up for braking to cause loss of traction. Modern ABS systems don't just pulse the brakes when the wheel stops spinning, it does so upon loss of traction. To determine whether traction has been lost, one wheel isn't enough of a sample size. The ABS works in tandem with traction control.
Regenerative braking cannot lock up, which is where the whole idea of calling it E-ABS got started, but it absolutely can still brake hard enough to cause loss of traction. I experience it all the time when slowing down on gravel with my electric skateboards, for example. It simply doesn't, and cannot, work the way ABS does on a mechanical braking systems, where braking is pulsed to regain traction the instant it is lost.
Yes, all ABS really means is anti-lock braking system, but what most people expect it to DO is to guarantee that traction is maintained while braking. (Even though that isn't technically correct, either)
EUCs?
Electric Unicycle. Like the Segway Z10 or the KingSong S18.
Electric UniCycles