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

Rick Osgood EMAIL HIDDEN
Wed Nov 23 20:25:30 PST 2011


This is really cool.  I had seen mecanum wheels before but not those omni
wheels.  There is a 3d printable Macanum wheel on thingiverse:

http://www.thingiverse.com/thing:2473

I wonder how well my thingomatic would be able to print one...

On Wed, Nov 23, 2011 at 7:44 PM, Mr. Clif <EMAIL HIDDEN> wrote:

> 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/Omni_wheel>
> http://en.wikipedia.org/wiki/**Mecanum_wheel<http://en.wikipedia.org/wiki/Mecanum_wheel>
>
> Kiwi Drive: http://www.youtube.com/watch?**v=ho7OK7Ylvu0<http://www.youtube.com/watch?v=ho7OK7Ylvu0>
> Mecanum Drive: http://techtv.mit.edu/videos/**629-holonomic-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<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.mathworks.com/matlabcentral/fileexchange/23931>
>>>>> http://www.msl.ri.cmu.edu/**publications/pdfs/isrr05.pdf<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_ICRA06_web.pdf>
>>>>>
>>>>> http://www.msl.ri.cmu.edu/**publications/pdfs/Ballbot_**
>>>>> TrajectoryPlanning_ICRA_2009.**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/BallbotTransition_ICRA._2009.pdf>
>>>>>
>>>>> http://www.msl.ri.cmu.edu/**publications/pdfs/**
>>>>> BallbotPhysicalInteraction_**HRI_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<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<http://www.ted.com/talks/peter_fankhauser_meet_rezero_the_dancing_ballbot.html>
>>>>>
>>>>> Clif
>>>>>
>>>>
>>>>
>>
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