Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

What do we want? Monowheel!

Since the dawn of the age of the automobile, motorheads have been obsessed with using as few wheels as possible. Not satisfied with the prospect of being incompletely maimed by a motorcycle, the monocycle was born. Gracing the covers of Popular magazines and other periodicals, these futuristic wheels of doom have transfixed hackers of all kinds. [James Bruton] is one such hacker, and in the video below the break you can see his second iteration of a 3d printed monowheel.

[James]’ wonderful monowheel is beautifully engineered. Bearing surfaces, gears, idlers, motors, and yes, twin gyroscopes are all contained within the circumference of the tire. The gyroscopes are actuated by a rather large servo, and are tied together by a gear that keeps their positions in sync. Their job is to keep the monowheel balanced at all times.

But as [James] discovered, the chief difficulty of only having one wheel isn’t lateral balancing. Ask any monocyclist and they’ll assure you that it’s possible. The real trick is balancing the machine fore and aft. Unlike a two wheeled velocipede, the monowheel has nothing to exert torque against save for a bit of gravity.

As [James] found out the hard way, it was within this fore-aft balancing act that the gyroscopic precession reared its ugly head. The concept is explained well in the video. We won’t spoil the surprise ending because the explanation and conclusion are quite good so make sure to watch to the end!

If you’d like to look at [James]’ first version, we covered it here. And if you’re the daredevil type, perhaps we can interest in you in a two stroke human sized monowheel that will probably end in an ER visit. At least they wore a helmet. Thanks to [Baldpower] for the tip!

10 thoughts on “Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

  1. How about two wheels, one inside the ring of the main traction wheel
    The second wheel would be a counter weight the primary wheel could use for deceleration. It would spin reverse of the traction wheel
    The cabin would then also use the secondary ring for position and stabilization by utilizing or when needed storing momentum in the secondary

  2. Veritasium actually covered a bicycle video on how we actually balance on wheeled self-propelled vehicles. He had several experiments on locking the steering after riding and it turns out the body makes micro movements left and right to compensate and balance, after locking the steering in a straight position you always fall almost immediately. The single wheeled device has as stated a forward and backward teeter to balance – but there is also left to right in there too. You should get some high speed photography of it moving, I wonder how the micro-oscillations contribute to the motion corrections – are they fast enough.

    I always wondered if the very low center of gravity actually hinders the ability to balance in these cases. Like those mopeds that have foot platforms at the bottom of the cycle that lower the gravity of the bike – they are fairly hard to ride compared to others that have a higher center of gravity.

    Still, very cool…..

  3. Don’t give up, you are nearly there!
    IMHO, It just looks like you need to keep the main unit with the gyro’s seperate from the wheel.
    By just adding one axis (let the wheel go left/right for a little bit seperate from the main body) it would simplefy the whole design and fix the issues.

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