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Build Your Own Self-Balancing Unicycle

Posted by michael on from the helmet-strongly-advised dept.

CaptainKaos[DOH!] writes "Robot hacker Trevor Blackwell is at it again, this time with a self-balancing Eunicycle. Blackwell writes, 'Some time ago I built a self-balancing two-wheeled scooter. Since then I realized that two wheels are redundant, and only a single wheel is needed to make a ridable vehicle. A vehicle with a single wheel is much smaller and lighter. It weighs under 30 lbs and is easily carried with one hand when going up stairs or on public transportation.' Trevor's previous 'Segway' type two-wheeler was mentioned on Slashdot."

3 of 197 comments (clear)

  1. Torrent for video by redhat421 · · Score: 4, Informative

    You can find a torrent for the video here: Park-all.lowbw.mpg.torrent

  2. Google Cache of site by SimCityHippy · · Score: 4, Informative

    http://66.102.7.104/search?q=cache:4K9GC46wUkAJ:tl b.org/eunicycle.html+&hl=en

  3. Re:At speed should be able to steer by leaning, to by Spy+Hunter · · Score: 4, Informative
    Gyroscopic effects are not the reason that works. You're thinking too hard. Turning the handlebars left is merely a way to lean right. It works at any speed, without any gyroscopic force, and is a necessary part of bike riding for everybody. (I believe that this simple fact is the one thing that you must "get" subconsciously when you first learn to ride a bicycle.)

    Turning by leaning does require gyroscopic force, but not in the way you describe. It is required to allow you to change your center of gravity by leaning. On a bike with no centrifugal force (a stopped bike), you cannot change your center of gravity by just leaning without turning the handlebars. If you could, it would be easy to sit upright on a stopped bike.

    When gyroscopic force enters the equation, it does allow you to change your center of gravity by merely leaning your body. Once you lean to the right and move your center of gravity to the right, you start falling over to the right. The reason you don't fall over completely is that the wheel also turns to the right of its own accord, which turns you and brings it back under the moved center of gravity. But the main reason for the turning not gyroscopic force; the real reason is the fact that the turning axis for the front wheel is not vertical. This means that when the bike is leaning to the right, the front wheel has a natural tendancy to turn right, even when stationary. Imagine a bike on its kickstand; the wheel is always turned in the direction of the lean, right? That's not a coincidence. This is the reason why you will never see a bike with a straight vertical rod connecting the front wheel to the handlebars. (or if you do see one, it will be quite hard to ride, and look stupid to boot...) Gyroscopic force also has an effect here, but it is not the main player.

    I found a cool site that explains it all: Motorcycle stability and steering.

    --
    main(c,r){for(r=32;r;) printf(++c>31?c=!r--,"\n":c<r?" ":~c&r?" `":" #");}