Smart Wheely

electric unicycle

I found this self-balancing unicycle via Trevor Blackwell’s site. Dr. Hofer’s self-balancing unicycle uses a wide tire for lateral stability. Trevor had spent several months learning how to ride a unicycle before building his; the large tire makes the learning curve for this one a lot less severe. The project site is in German, but I found one write-up in English. The majority of it is dedicated to the control scheme. It is very difficult to model the unicycle as an inverse pendulum due to so many unknowns. Dr. Hofer’s team used fuzzy control instead which let them apply several layers of rules without requiring a lot of previous knowledge. Here’s a photo gallery of the device.

[sean] reminded me that I forgot to include the obligatory link to Bombardier’s Embrio concept.

17 thoughts on “Smart Wheely

  1. I saw a video of this device a few years ago where the inventor was being interviewed at some sort of expo. The interviewer took it for a few laps and then as he stepped off and took his hand off of it, the cycle sensed the imbalance, overcompensated, and went into a cycle of rocking violently backward and forward until it fell completely over and started rolling away in a horizontal position. Very surprising and funny. Naturally, I immediately started wondering if there’s a way to make Segways do that… If anyone works that out, you’ll have my eternal gratitude.

  2. down the bottom of that english writeup: “The transport of goods, materials and other objects on a single wheel was formerly quite impossible, as these items were not themselves capable of balancing the unicycle.”

    bah, I carried a large string trimmer/edge trimmer about 5kms on a 24″ (mechanical/standard) unicycle. I’ve ridden with people on my shoulders. It’s not impossible, on the contrary, it’s perfect when you are going to buy some milk and a newspaper because you have your hands free to read the paper on the way home.

  3. I cant help but think the engine is a little oversized in the second link on post 3. Either that or hes going for the land speed record on a monocycle!

    @4 – I very much doubt you could get a segway to do this. Its probably got a feedback system that is tuned better than what that guy had. However I wonder what would happen if you were to pick the segway up, rotate it say 50 degrees and drop it back down again. Anyone whos got one give it a go for us… :-)

  4. #8 that monocycle does hold the land speed record.

    “loosely coupling two unicycles with a cross-bar also allows stable single-axle vehicles to be implemented for the first time ever.”
    segway? impressive, if he didn’t have the segway around for inspiration. maybe even grounds for a lawsuit?

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