Where for art thou non-motorised Segways?

[cmonkey]

ok, what's the word for the artistic conveyances that sometimes show up at the doo dah parade in pasadena?

I remember a 'self balancing' machine that was in the parade.

Just like the dino toy.... the riders sat in such a way that more than 50% of their mass was below the axle. This way they only needed the two wheels for support. Needless to say the contraption had twelve foot diameter wheels and could seat something like 4 or 6 people, but I'm sure something could be made up that would fit a child.

edit: Kinetic sculpture?!?
http://images.burningman.com/index.c...yword=&q_year=

[BrettCMSmith@gmail.com]

Bystander and KSagal have done some work and figured it out for me.
Ive had a good look at The Magic Wheel as quoted by Bystander and it rotates from the axle height but the weight of the rider is resting at a lower point, giving a lowered COG and greater stability.
It turns the reverse pendulum of a Segway into a simple Pendulum where the axis/axle is higher that the weight.
Its the same principle as the item that Karl Sagal has shown, where not all the weight is under the axle but the lower the weight is under the axle, and/or % of weight, the more stable.
Both of these examples use the same principle that I am interested in replicating. And both of them seem stable enough to follow their lead.

Consider a 20" wheel and a 36" high rider, add a Seg-like vertical post and handle at the front for more control and the idea looks do-able.
In theory.....

Just keep the axle high and the weight as low as possible. Remember its just a kids toy.

Thanks guys, I wont give up till Ive made one but if theres anyones who'd know how, it'd be one of you.
Thanks for the links Polo, those people are way smarter than me.

Best wishes guys, Brett.

Anyone else from Australia out there? Someone else must love Segways in Australia?

If someone wants to add to the idea without doing their thinking in public, please email me at my highly secretive email address.

[KSagal]

THe concept of sitting below the axle in a 12 foot wheel device is not new, several exist that have only one wheel...

I believe the problem with a simple pendulum weight for stability, is that there is a point of speed and resistance where that is just not enough. The velosity will pitch the weight back, and on stopping, the weight will rotate forward, and if there is enough torque, or braking input, the oscillation could be quite a bit.

One last thing... I don't involve myself in Burning Man much, and was under the impression that it was all about free expression, but doesn't anyone there own a pair of pants?

[BrettCMSmith@gmail.com]

To cmonkey, TESTIFY !!
You got the idea worked out too, but I dont think that Burning Man is really my style at all.
However the picture is an example of the idea I envision, just a warped XXXXXL version.

KSagal, I can definately see the concept you have about the momentum moving forward and back as energy is added or removed and how it would upset the stability of the unit progressing and stopping. Its the main concern for me considering that a non-gyro Seg-vehicle has little longitudinal stability. There could be a limiter on the axle so the footplate cant rotate/swing too far forward or back. Plus the upright handle should/will give stability similar to a standard scooter. Larger diameter wheels will help too.Anything else?
I know thats not a clear or total explanation but I can E-mail pics of possible variations if required.

Its a point I have considered but not solved as its one that needs to be seen and considered as a prototype is built.
This is something built from the ground up so it could be modified in any way but all the bugs are just something to solve as they appear, Im not bothered by that aspect.

Good to see a few others willing to add, thanks again, Brett.

[bentbiker]

Originally Posted by BrettCMSmith@gmail.com

Consider a 20" wheel and a 36" high rider, add a Seg-like vertical post and handle at the front for more control and the idea looks do-able.
In theory.....

Just keep the axle high and the weight as low as possible. Remember its just a kids toy.

Once you have your sketch with dimensions, I'd encourage you to do a moment analysis of the forces involved. As soon as you add that vertical post and a child leans forward against it, there is quite a moment applied to the platform about the axle. As the platform tilts, more force is applied to the post, and and the moment increases.

Also, the size of the platform is limited by its proximity to the ground; as the platform tilts, the front edge will (if too low) hit the ground and allow the child to do a faceplant. Rough numbers say that a platform 2" off the ground in your design would strike smooth ground when tilted forward if the front edge extends as little as 6" forward of the axle (12" centered platform). Slightly raised irregularities make the situation worse.

I wish you all the best, but I suspect there is a reason this design doesn't exist in the marketplace. Have you ever heard of people trying to use a hand truck (as used by movers) to coast downhill?

[KSagal]

Actually, I have a garden cart with a design of this sort. It is late here now, so I will have to go out to the shed and post a picture tomarro.

My cart has a deck about a meter long, by a bit more than half that wide, on 14 inch wheels. The deck is about 4 or 5 inches below the axle (Split, one for each wheel).

I have added a tongue so I can pull it with a lawn tractor, and it came with an upright set of handles, not entirely unlike what was described.

I will post photos later, but the point of it not being a good device for gliding is very valid. It is much more in the neighborhood of a wheel barrow, in that it requires a walking user, and the support of that user at one end to make it workable.

[BrettCMSmith@gmail.com]

Hi John and Karl.
John, I will certainly take your advice and do the math on the forces involved as I get some realistic dimensions worked out.
As for the ground clearance, the Razor scooter has a clearance of 4.5cm or 1.5 in ( all my mearsurements are approx so dont shoot me if I miss by a fraction due to international variations.)
If I was using a 20" wheel that gives a drop from the axle to the platform of 8.5" of thereabouts,so that gives a comfortable variation in height and a ground clearance of 1.5", which puts in right at an acceptable level set by the prior art.

Now the important thing in order to avoid faceplants, as I see it, is the size and shape of the platform.
Heres a few options to consider....
1. If its going to be pushed along like a skateboard/scooter, it needs room for a foot to be extended out forwards and towards the ground in order to provide propulsion, but with 20" wheels, thats too high to expect a child to lift their leg over a wheel that high and back everytime to propel the device. So you'd have to provide room for a swinging leg to propel the device between the 2 wheels. By example,a Razor scooter has a footplate 11" long by 4" wide.So the platform could be quite small and oriented in any direction.

2. I noticed that as I stand on a Segway that the combined weight at the front of the vehicle and my own weight distribution was not exactly over the axle of the Segway but slightly aft,( but that might have something to do with the size of my aft. ) irrespective of the angle of the Segway, so a platform would not necessarily extend as far forwards beyond the axle as it is backwards or the importance of the front of the platform was not as important as the rear area. This balance can be demonstrated by standing up and then extending your arms forward, I tend to lean back slightly so my COG is slighty behind where it is if Im standing straight up. (Sorry to be confusing.)

3. If the platform had a rolled front and rear edge that had just enough curve upwards then it might not contact the ground at all. Kids have small feet so I dont see why the platform has to be overly long from the front edge to the back, maybe 8 inches ? so not too much curve might be easily incorporated to ensure clearance.

4. Possibly a skid plate on the underside like skateboards used to have in the 80's, anyone remember them?

5. This is not a perfect option now, but if the other methods didnt work then theres the slightest possibility that a small third skateboard wheel just might be required to ensure stability but only if all the other options failed. It might only be required as a training wheel initially?? I see it as a bit of a failure to use any more than 2 wheels.

I think that the reason why it doesnt exist in the marketplace is reason enough to try it. Theres precedence for the physics,and if you saw it in the shops we'd all say " D'oh ! Why didnt I think of that?" But if I kill myself on it you can say " I told you so" too !

Karl, l think I understand about your garden cart but I think the closest cousin I can offer to my idea is if you connected 2 Magic Wheels side by side with a lowered platform and added a front handle. Thats not too far-fetched, or is it?
Thanks again and does anyone know how to post pix straight from a computer or do they have to be posted elsewhere and linked??

Regards, Brett.

[bystander]

Originally Posted by BrettCMSmith@gmail.com

Thanks again and does anyone know how to post pix straight from a computer or do they have to be posted elsewhere and linked??

Regards, Brett.

Since you are a new user on this board, you may not have full access to the attachments system. Once you make enough posts, you will see a button entitled "Manage Attachments" down below in the "Additional Options" section.

You should be able to upload small attachments directly with your posts.

If you need to upload larger photos, you will have to use the Coppermine gallery. To get started with that click on the "Photos" link in the upper right of this page.

Also, try searching this board for the term "Coppermine" for more tips about using it.

[BrettCMSmith@gmail.com]

Bystander, every forum is different and a helping hand for a newbie is always welcome.
Thanks mate, Brett.

[KSagal]

I took some pictures in the rain of my garden cart. It is far from a segway, but you can put very heavy weights and they stay very stable...





The cart is old, and the paint is peeling from the wheels, but it works well...

One thing you may notice is that I found that sloping the platform up both at the front and back works well to reduce and all but eliminate bottoming out. (This platform is significantly longer from front to rear than yours would be...)