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Author Topic: Pigeon-toed gyropod  (Read 907 times)

Jeremy McCreary

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Pigeon-toed gyropod
« on: January 22, 2018, 06:31:06 PM »

This simple motorized kneeless walker travels with a gyroscopically driven shuffling stride. The onboard motor just spins the flywheel and forces it to nutate (nod up and down). Reactive gyroscopic torques acting on the rapidly spinning flywheel and the chassis do the rest.

https://www.youtube.com/watch?v=3KCg2zI0kfI

As you can see at 0:47, net travel without the spinning flywheel and its large axial moment of inertia is nil. That's because the forward steps are actually gyroscopic precessions induced by the flywheel's forced nutations.

Operation couldn't be simpler:
o Use full power to get decent travel speed.
o Reverse the motor to reverse the direction of travel.
o Pull gently on the "leash" to steer.

Noted roboticist John Jameson introduced the first "Walking Gyro" in 1981. The concept soon made its way into at least 2 commercially successful walking robot toys, and a number of DIY versions have popped up on YouTube in recent years...

https://www.youtube.com/watch?v=8qM3Bao3zJQ

https://www.youtube.com/watch?v=HJPlPwwR8Ak.

This is the only LEGO version I know of. Its feet don't lift completely off the ground, but even a shuffling gait took a tremendous amount of fiddling with flywheels, spin transmission ratios, and most of all, the feet! The foot disks used in most walking gyros failed miserably, as did nearly every other foot design I tried. The bird feet shown here emerged after hours of trial and error. And they work only when pigeon-toed, as shown.

Photos and write-up here.
« Last Edit: January 22, 2018, 06:40:38 PM by Jeremy McCreary »
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Playing with the physical world through LEGO

ta0

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Re: Pigeon-toed gyropod
« Reply #1 on: January 22, 2018, 10:51:59 PM »

Very interesting project!  8)

I wasn't aware of this application of gyroscopic reaction and I love it!
I'm tempted to move it to a Spintop-Related section.

Thanks for posting it.

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Beylon

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Re: Pigeon-toed gyropod
« Reply #2 on: January 23, 2018, 12:10:00 AM »

So awesome. I've always loved GyroMan! In many ways, the feet of yours make it look even more cute. Like a jelly-chicken.

I actually did a lot of work with shufflebots back in the early days of my project:

https://www.youtube.com/watch?v=uOLZPsR0bt0

Sorry about the vid embed, I can't seem to get it to appear as text. I often wondered if the mechanism could be described the same way as it is in GyroMan. Remember that a horizontal-axis flywheel is essentially unbalanced on the downstroke... So its basically a counterweight. Which is very shuffley.
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Jeremy McCreary

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Re: Pigeon-toed gyropod
« Reply #3 on: January 24, 2018, 02:56:35 AM »

Thanks, everyone.

I often wondered if the mechanism could be described the same way as it is in GyroMan. Remember that a horizontal-axis flywheel is essentially unbalanced on the downstroke... So its basically a counterweight. Which is very shuffley.

Those shufflebots are pretty cool. Not sure I follow the comparison, though, or the part about horizontal-axis flywheels.
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ta0

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Re: Pigeon-toed gyropod
« Reply #4 on: January 24, 2018, 10:47:08 AM »

The shuffle bots using eccentric flywheels are very cute. The mechanism is very different to the gyro man that works using the precession of a balanced flywheel.

I think it's great that you documented the development of your Silver Shells and made a video about them. I'll start to do the same with a project I have (which probably won't go to Kickstarter until a couple of years from now as I want to have a patent close to issuing before I do).  :-X
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jim in paris

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Re: Pigeon-toed gyropod
« Reply #5 on: January 26, 2018, 12:27:58 AM »

hello

These shuffle bots are incredible !
thanx for showing , it gives the envy to build a couple  ;D

jim
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