[Discuss] Cool 5 minute talk about a Ball bot.

Mr. Clif EMAIL HIDDEN
Wed Nov 23 19:44:53 PST 2011


So it turns out that the three rotor drive is called a Kiwi Drive, and 
the rotors are called Omni wheels, which are related to Mecanum wheels. 
Notice it says "... will also slide laterally with great ease." Hence 
"sliding wheels".  ;-)

http://en.wikipedia.org/wiki/Omni_wheel
http://en.wikipedia.org/wiki/Mecanum_wheel

Kiwi Drive: http://www.youtube.com/watch?v=ho7OK7Ylvu0
Mecanum Drive: http://techtv.mit.edu/videos/629-holonomic-drive

     Ciao,
     Clif

Mr. Clif wrote:
> Hey Robert,
>
> Shell I sign you up to EMS Discuss?
>
> Robert Kelley wrote:
>> I am guessing the three driving axles are orthogonal, and if extended,
>> would intersect as the corner of a cuben
> Ah, so that would make the down tilt 45 degrees then. The more it goes 
> down the higher the "gear ratio" of the ball is. If the rotors were to 
> move up and down on the ball it would act like variable speed 
> transmission, and at the "equator" it would be infinite as you would 
> only be able to spin in place, no lateral movement would be possible. 
> Therefor I'm thinking that having the rotors as close to the top as 
> practicable is best.
>> I am wondering if the driving wheels have tangential rollers on them.
>> These guys used gear head motors.
> Ofcouse they are, that's what I ment by "those fancy sliding wheels" 
> below.
>> I wonder if we could fill an inflatable ball with some liquid that
>> will set up.  Epoxy?  Urethane foam?
> I suppose you could but it wouldn't be quite round and it wouldn't be 
> springy either. Wouldn't it be better to just use a basket ball with 
> air in it? :-)
>
>     Clif
>> On Wed, Nov 23, 2011 at 11:03 AM, Mr. Clif<EMAIL HIDDEN>  wrote:
>>> Hey Robert!,
>>>
>>> I just sent a link for that to the Maker Space discuss list (CCed 
>>> above).
>>> ;-)
>>>
>>> My video player happened to freeze at just the right frame for me to 
>>> see
>>> that there are three largish ball bearings on the bottom pressed in 
>>> with
>>> spring steel. At the top of the ball it only contacts the three driving
>>> wheels. The three axis are obviously at 120 degrees, I wonder if the 
>>> down
>>> tilt is also 120? ;-)
>>>
>>> Yes it does look like a fun project doesn’t it? Reminds me of the 
>>> home built
>>> seguways that this guy from hackers was making on the cheep. He 
>>> would have
>>> parts for sure. Hmmmm....
>>>
>>> So you need at least a good six axis accelerometer, Three motors and
>>> drivers, Controller and batteries! Oh, and those fancy sliding 
>>> wheels would
>>> be handy too. :-D
>>>
>>> Clif
>>>
>>> Robert Kelley wrote:
>>>> Check out this amazing TED Talk:
>>>>
>>>> Péter Fankhauser: Meet Rezero, the dancing ballbot
>>>>
>>>> http://www.ted.com/talks/peter_fankhauser_meet_rezero_the_dancing_ballbot.html 
>>>>
>>>>
>>>> I like the human scale of it, though smaller ones have been built.
>>>>
>>>> Larger ones could be ridden.
>>>>
>>>> The devil is in the details, I suppose.  Do you suppose the ball cage
>>>> is lined with rollers, or Teflon?
>>>>
>>>> The ball is rigid, rubber coated, like the ball of a mechanical mouse.
>>>>
>>>> Do you suppose the three axles are orthogonal?
>>>>
>>>> http://www.mathworks.com/matlabcentral/fileexchange/23931
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/isrr05.pdf
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/ballbot_ICRA06_web.pdf
>>>>
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/Ballbot_TrajectoryPlanning_ICRA_2009.pdf 
>>>>
>>>>
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/BallbotTransition_ICRA._2009.pdf 
>>>>
>>>>
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/BallbotPhysicalInteraction_HRI_2009.pdf 
>>>>
>>>> http://www.msl.ri.cmu.edu/publications/pdfs/Ballbot_ShapePlanner_RSS.pdf 
>>>>
>>>>
>>>> Got any pieces?
>>>>
>>> Mr. Clif wrote:
>>>> Here is a quick demo about a bot that balances on a ball.
>>>>
>>>>
>>>> http://www.ted.com/talks/peter_fankhauser_meet_rezero_the_dancing_ballbot.html 
>>>>
>>>>
>>>> Clif
>>>
>




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