Self-Balancing One-Wheel Motorcycle Tears Up The Beach

[XenonJohn] wrote in to let us know about updates and a recent test drive of an Electric Self-Balancing One-wheeled Motorcycle, fresh from the beach where he says it proved to be great fun to ride. The design and build have been updated since we last saw it as a semifinalist entry in the 2014 Hackaday Prize. The original, he says, “looked cool but was slow, cumbersome and really dangerous to ride.”

electric self-balancing unicycle - thumbnailSince then it has been completely redesigned and now has a super fat kite-surfer wheel, a front crash skid with damper, and a variable geometry which allows it to steer properly despite just having one wheel. It does this by allowing the rider to shift their position relative to the wheel, instead of the seat always being rigidly locked directly above the axle.

That steering is a pretty clever upgrade, but we do wonder if the new crash skid will have an atlatl effect and really launch the rider in a crash. Our gut feeling aside, it is designed not to plant itself in the pavement, but to slide along (without ejecting the rider) until the vehicle loses all momentum.

There is something about self-balancing unicycles that attracts experimenters, each of whom takes a different approach. We see everything from this device constructed mainly from a Razor Scooter to this more polished-looking unit based on an earlier Segway clone design. [XenonJohn] reminds us that “there is still much to learn in this area and you can genuinely innovate even as a hobbyist. Also, you can only do so much on a computer, you then have to actually build something and see how well it works. [This recent test] shows what you can do if you just keep on experimenting.” Video of the test drive is below.

The project’s site has plenty of additional information, as well as a collection of photos of similar machines from around the world including art concepts. [XenonJohn] says that after years of work, he’s finally happy with the current unit and is next going to make it easier for others to build their own. If he decides to have a run at one of the 2016 Hackaday Prize categories, there’s still plenty of time!

41 thoughts on “Self-Balancing One-Wheel Motorcycle Tears Up The Beach

  1. With the wind in the gif sequence it looked like he was going upwards of 40 mph, I was a tiny bit disappointing by the speed in the video. A rad piece of engineering regardless!

    1. I suspect that even at the relatively low speeds achieved, he felt like he was going 100+. The sensation of speed has to be pretty extreme when you don’t really have any of the machine within your field of view.

  2. Interesting and challenging hack from a technical perspective. But I can see a problem with it – that is sudden braking = the rider being tossed over the handle bars and doing a nasty face plant. .

    1. Sudden braking on a machine like this should never be a problem (remember it’s only going about 15mph), there are no mechanical brakes and so the wheel never just stops, a couple of mechanisms can be used to slow/stop a mono wheel vehicle such as this,
      – With control mechanisms that require the user to disrupt the balance by leaning/pushing on the handle bars (think Segway) all the rider needs to do is stop pushing – if you want to stop in a hurry then you can lean back.

      – A slightly more advanced way of stopping a machine like this, if you momentarily speed the unicycle up beyond what is required to balance the rider, it will tip the rider backwards behind the balance point, the unicycle will then stop quite quickly.

      The only way you will ever find yourself flying over the handle bars is A) if you suffer some sort of mechanical mishap, or B) if you ride into something unmovable, and I imagine both of these situations would just as easily unmount somebody riding a normal motorcycle.

      This isn’t to say such a device is foolproof, but then I fell of my bicycle a couple of times before I finally got the hang of riding it.

  3. Thanks for the comments. In terms of top speed you are correct in that you are mainly limited by your personal fear. I have face-planted on tarmac (video already on YTube for you to laugh at) with a full crash helmet on and it still hurt a lot. The skid was fitted after that. It tended to stick to tarmac and not actually “skid” at all so now it has 2 small wheels concealed inside. This is what I mean about building and testing repeatedly to see what works. They work fine on tarmac and you do roll to a stop. On sand it probably would still not work very well but at least the landing is softer. The machine is slim when viewed from above with fairly smooth sides, this helps a lot if you bail out and jump off it to one side. The first one had a motorbike fairing which looked good but your legs got tangled up in it if you fell off. The targets at this stage were simply making it easier to ride and getting a decent steering system working. They have been achieved. Braking is easy actually, there is a twist grip on the left handlebar that adjusts the balance angle, you make it lean back to slow down. It also automatically leans back if you exceed 80% of max motor power. The power question is interesting. The battery lasts far longer than I would expect. If you think about it it only has to overcome the rolling resistance of one wheel, plus wind resistance. It also has regenerative braking so even though it accelerates then slows almost imperceptibly at rapid intervals to keep self-balanced, you could argue some of the energy is recovered as it does that. Gradual turns can be done by gentle weight shifting, for tight turns you turn the handlebars and the frame changes shape so you end up running on inside edge of the tyre. The reason for doing it? The challenge of doing something that defies most notions of what is possible of course and the challenge of developing something genuinely original during your lifetime. It is also simply really good fun to ride for a mile or two on it along a deserted beach. Riding it is like sitting on some kind of living animal as it feels more like you are persuading it to do what you want it to do than fully controlling it! In the selfie shot you can see it performing a lot of small movements all on its own independently of my own control inputs. Regarding plans, the welded tube frame has ended up overcomplex and now the whole hardware design needs to be simplified so can be bolted together from laser cut panels or similar.

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