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Not a Wheelchair [video]

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Re: Not a Wheelchair [video]

#71

Post by black_puppydog »

codekansas wrote: post #45

Reminds me of this passage from Cory Doctorow's book Walkaway: "You realize that they're exactly right," Sita said. She smiled, stopped. "You know, when the first walkaway prostheses project started, most of the people contributing had lost an arm or a leg in Belarus or Oman, and were tired of paying loan sharks for something that hurt and barely worked and could be remotely repossessed by an over-the-air kill-switch…

Gosh I really love-hate that book. It comes up over and over and over again despite what I consider shoddy writing. It's a bit of a blueprint for how to make the best of a foreseeably shitty future.

Re: Not a Wheelchair [video]

#72

Post by beenBoutIT »

Skunkleton wrote: post #60
a-wu wrote: post #32

Earlier quoted context omitted.

I mean, speaking for myself mainly here, but I wouldn’t really feel comfortable in _any_ off-road situation without a buddy with me. And most of my friends who handcycle regularly generally always have someone with them. But then again I don’t want to exclude the population who are capable of doing this independently.

Able or not, it is usually a good idea to have a buddy when you do this sort of thing.

That thing gets a flat tire or rolls over and a buddy is going to come in real handy.

Re: Not a Wheelchair [video]

#73

Post by black_puppydog »

tsumnia wrote: post #62

Most of the comments have criticized the price point for what you are getting; however, I would say this looks like a great quality of life tool for disabled individuals. If you are wheelchair bound, there are a number of terrains that a traditional wheelchair will not operate on. They even point this out with their rig on beach sand. There are designs that handle sandy terrain [1], but they would not work well on ot…

The price point for the beach wheelchair you linked is $2,440.00. That's about half the price of this rig, and it does not get you to the beach. You need to have (and park/stash?) another wheelchair for that. Oh and you have to have someone push you.

By the way, I read @codekansas' comment [1] not as a warning about feature creep, but as a comment on the inertia in the medical industry (emphasis on "industry") versus just a few enthusiasts who don't feel bound by patents, conventions and markets, and simply want to build something to improve their lives.

[1]: https://news.ycombinator.com/item?id=23703179

Re: Not a Wheelchair [video]

#74

Post by geocrasher »

uoaei wrote: post #66
geocrasher wrote: post #49

Earlier quoted context omitted.

Indeed, this thing will likely eat tires if used on-road a lot. Without a differential, it'll also be harder to steer and will want to "push" through the turns. You can see this at 2:31: https://youtu.be/vuMg0QwKAGI?t=151 The turning radius isn't that great, and the lack of a differential helps explain why. Definitely an interesting design choice.

Version 1.0 will always be a functional proof-of-concept. They have the basic platform, now they can start iterating.

If they've gotten this far, they've already been iterating. In fact he says so at the beginning. "A year ago I welded two bicycles together..."

Having built two recumbent vehicles (a bike and a trike) I can say that the options for a rear wheel drive are either:

- Single wheel drive

- Dual wheel drive with freewheeling action

   - The inside wheel is driven in turns
- A differential

   - The outside wheel is driven in turns
- No differential at all

   - Both wheels are driven equally all the time
He's chosen the latter. It's simple, cheap, and provides the best traction in almost every situation except a turn. It's a good compromise for where this thing is intended: Dirt. If it were optimized for street use, he'd just drive one wheel, which is what I'm doing with my own trike.

For reference, this is my current trike build. It's not done yet. Needs finishing, and paint:

https://i.imgur.com/pnrDQMS.jpg https://miscdotgeek.com/wp-content/uploads/2019/11/IMG_20191...

Re: Not a Wheelchair [video]

#75

Post by theqult »

Something that is not a wheelchair is the Genny. I used to work there in IT Dep. many years ago and still i think is the only real useful application of a Segway. And the best part it doesnt't look like a fucking wheelchair, when i was trying it many people stopped me and ask if they could try it. luckly for me, I'm not paraplegic so they had a ride. The only const: Is not that cheap, 20K Euro. But if don't live in a retarded country (yes US, I'm talking about you) the biggest part is on the state

https://www.gennymobility.com/int/products.html

Re: Not a Wheelchair [video]

#76

Post by djrogers »

theqult wrote: post #75

Something that is not a wheelchair is the Genny. I used to work there in IT Dep. many years ago and still i think is the only real useful application of a Segway. And the best part it doesnt't look like a fucking wheelchair, when i was trying it many people stopped me and ask if they could try it. luckly for me, I'm not paraplegic so they had a ride. The only const: Is not that cheap, 20K Euro. But if don't live in a…

> if don't live in a retarded country

Probably not the best terminology to use on a post about people with disabilities.

Re: Not a Wheelchair [video]

#77

Post by mlyle »

Someone wrote: post #47
Someone1234 wrote: post #31

Earlier quoted context omitted.

Given that the electric monitor is in-line, and there's no gearing or shaft, I mean is that such a stretch? The easiest way to make it 4WD would be a second electric motor, which could easily be 30%.

Driving the front wheels is more complicated because the front axis is used for steering (it might be easier to go for two motors there, and, if you go there, 4 identical motors might be the better choice for maintenance/repairability). I think you also would need to guarantee that both engines are aiming for (about) the same speed, even in corners or when tire pressure changes. That might require something technical…

> I think you also would need to guarantee that both engines are aiming for (about) the same speed, even in corners or when tire pressure changes. That might require something technically similar to ABS.

Equal torque is good enough. They'll settle to speeds consistent with turning, etc.

Since they're independent motors, you don't need to worry about the case where a wheel is spinning stealing all of the torque.

> Also, does this have a differential on the back axis? I couldn’t spot it, but that may be because I don’t know what they can look like on these relatively low-powered devices.

I don't see it. Often ATV, etc don't have them: you get enough wheel slip on low traction surfaces that turning works fine, and the prospect of one wheel with impaired traction stealing all the torque is bad.

There's those Russian sidecar bikes.. they have just a clutch for the second rear wheel. If you're on a paved surface, you use one driven wheel, but if you're offroad and could use 2WD, you can engage the clutch (and slippage does the job of a differential).

Re: Not a Wheelchair [video]

#78

Post by jacquesm »

They're going to sell very large numbers of these. In the same week that the SegWay is EOL'd this comes out. If 'It' had been this it would have been a damn sight more impressive. Great work, great people.

Re: Not a Wheelchair [video]

#79

Post by theqult »

djrogers wrote: post #76
theqult wrote: post #75

Something that is not a wheelchair is the Genny. I used to work there in IT Dep. many years ago and still i think is the only real useful application of a Segway. And the best part it doesnt't look like a fucking wheelchair, when i was trying it many people stopped me and ask if they could try it. luckly for me, I'm not paraplegic so they had a ride. The only const: Is not that cheap, 20K Euro. But if don't live in a…

> if don't live in a retarded country Probably not the best terminology to use on a post about people with disabilities.

Probably the pickiest comment i ever received

Re: Not a Wheelchair [video]

#80

Post by jacquesm »

undersuit wrote: post #23
pkulak wrote: post #11

Earlier quoted context omitted.

Far more stability, right? I assumed that's why 3-wheel ATVs are banned pretty much everywhere.

Having the front be single wheeled leads to the a lot of instability because turns change your center of gravity. I just bought a recumbent bike and I had to search extensively to find a nice two-wheeler because the 2 front wheel 3-wheelers are quite popular, just like the motorcycle equivalent. Most bikes and motorcycles with three wheels have the same steering linkage you'd find in a car.

Be very careful with two wheel recumbents, I've got half an Ikea's worth of steel bits in my right leg on account of one. The danger is in when your foot slips off the pedal even for a moment and hits the pavement on the downstroke, you'll brake with just that one foot and it is a feed-forward mechanism that you can not break out of. Nasty, to put it mildly. If I had foreseen that particular failure mode I'd have either foregone the bike entirely or I would have placed something underneath the cranks to catch my feet should I ever go there. The lower the bike the higher the risk of this happening.
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