1-wheel Segway?

Bombardier “Embrio”:


There was a thread a while back about this, called something like ‘I Found my New Wheel’.
I would love to own one, but it’ll cost probably as much or more than the Segway. Which isn’t actually as good as it sounds (revolutionize the world… Yeah, whatever…).

Re: 1-wheel Segway?

DANG!!! I’m working on the same basic idea… Their design looks exactly like what I’ve been doodling in my spare time. There are a few details I’d change, but basically it’s the same thing as my next-step manned vehicle.

Ah, well, it looks to me like Bombadier isn’t serious about the design; or at least, they aren’t serious about this concept machine:

“The Embrio is powered by a hydrogen fuel cell, a technology that creates power by mixing hydrogen and oxygen, ideally resulting in water as the only exhaust.”

Fuel cells for small vehicles are a long, long way off. At least 10 years, perhaps 20. They work great in clean lab environments, but in the real world there are serious problems with fuel contamination, operating temperatures, duty cycles, etc. But it sounds good in a press release, and the cool design gets the Bombadier name in the papers.

Ah, well, perhaps I should give them a call to see if need consultants. I wonder how much they will have to pay Segway for royalties? The Segway patent claims single wheel vehicles too.

I like the line:
The vehicle is made of lightweight materials, like aluminum, magnesium and nylon. It weighs only 360 pounds.

Well, gee! Only 360 pounds! That’s three times as much as me!

I just crunched the numbers for longitudinal stability. The doubling time* for power-off stability is surprisingly close to a normal unicycle - about 0.1±0.01 seconds for “the beast,” and 0.137±.05 seconds for a 20"X2.5" uni with a 170 cm, 70 kg rider. (Coker doubling times are on the order of 0.15 seconds for the same “standard” rider, BTW.)

What that means is that if the power or control systems fail on this thing at 75mph you’ll UPD about as fast as you did when learning to ride… and thats if the wheel is free to spin. (If the wheel locks up you won’t even have time to think “Whump!!”)

I’m sticking with robot Unis! This thing makes rice rockets look positively safe!


    • Doubling time is the time it takes for a tipping error to double; i.e. it takes about 0.137 seconds for a 1 degree tilt to turn into a 2 degree tilt, then in another 0.137 seconds that turns into a 4 degree tilt, and so on.

PS: I just checked the Bombadier site. The division that put this concept vehicle out isn’t hiring. That’s usually a sign of serious interest, so this is really just a clay model.


I would imagine this is a long ways off, IF it is even being considered for production, which I doubt…

But man it is cool…

– mark

Re: Re: 1-wheel Segway?

I believe the article mentioned a projected ship date of 2025, which would seem to align with the timing you mention for suitable progress in fuel cell technology.

There have been at least two other threads on this topic, although I can’t remember whether they delved into the scientific as this one does, or whether they stayed on the various iterations of “wow, cool”. The first which I started is here: http://www.unicyclist.com/forums/showthread.php?s=&threadid=26604

There is a video of a self balancing robotic unicycle here:
Athena Technologies video gallery
The robot was made in 1992 (Hmmm, sounds like it was before Segway). It was a project done for MIT.

Cool stuff.

The MPEG version of the video clip cuts out half way through. The QuickTime and Windows Media versions are better.

VERY COOL!!! And these guys are right down the street from me… Road trip!



A technical university in Germany made a robotic unicycle that you could actually ride.

Go to their home page: Fachhochschule Bielefeld University of Applied Sciences
Scroll down to the bottom of the page to the search box (or Suche box). Do a search on “einrad”. That will bring up pages about the unicycle.

The Babel Fish at AltaVista.com comes in very handy for reading the site.

Pictures and video clips
Project page
English tech article

Also http://dict.leo.org

Klaus Hofer’s work is a good example of the German standard for engineering education - a Fachhochschule is basically a vocational tech college that gives out degrees in, say, welding or machining. It’s not a technisches Universitat where their best and brightest go, yet they made this uni from scratch. Impressive, na?

Hofer’s student’s machine doesn’t do lateral balancing. The big roller gives passive stability, which is fine for floors but doesn’t cut it outdoors.

A practical robot unicycle should at least be able to idle, so I’m working on a Java 3D visualization of a robot sim (using Kane’s equations of motion and fuzzy logic). It’s recreational project that is really taking a back seat because my day job just got interesting again.

(Oops, I did it again. I used the word “practical” in the same sentence as “robot unicycle.” Gotta get more sleep!)

Thanks John,


There’s another take on the Segway Uni at the Popular Science website: