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 Robotics / 4100
4099  |  4101
Subject: 
Re: Three-wheel Synchro Drive
Newsgroups: 
lugnet.robotics
Date: 
Wed, 3 Mar 1999 19:56:03 GMT
Viewed: 
902 times
  
Jonathan Knudsen wrote:

Yes, ideally the wheels should be placed on their axis of
vertical rotation. The solution I adopted was to try to
offset the wheels from the vertical axis by their radius.
The robot I built does turn in place, almost without moving.

There was quite a bit of discussion on the difficulties
of synchro drive on this list. If you're interested,
go to the discussion group area at
http://www.lugnet.com/ and search for "synchro drive".

Jonathan

I do not believe trying to center the wheels on their axis of vertical rotation
is a good idea.  Although doing so would drop the amount of motion in the
platform to virtually zero when the wheels are changing directions, it also has
the undesirable side effect of directly fighting the friction between the ground
and the tires.  Keeping the wheels off-centered makes it so that the friction
between the ground and the tires would cause the tires to spin, which does all
the work necessary to compensate for the friction, thereby increasing the
longevity of the tire treads, and reducing the amount of work necessary to change
the tires' direction.   If this isn't making sense to you, think about what
happens when you try to steer a car while it's parked or otherwise not moving.
Of course, if you always plan on having the platform in motion,  then it's not
really an issue becase the wheels will always be turning, but if you wanted it to
stop, turn, then proceed again, then what I'm talking about here should be of
some concern.

Mark



Message has 1 Reply:
  Re: Three-wheel Synchro Drive
 
Mark Tarrabain writes: > I do not believe trying to center the wheels on their axis of vertical rotation > is a good idea. Although doing so would drop the amount of motion in the > platform to virtually zero when the wheels are changing directions, (...) (26 years ago, 3-Mar-99, to lugnet.robotics)

Message is in Reply To:
  RE: Three-wheel Synchro Drive
 
Yes, ideally the wheels should be placed on their axis of vertical rotation. The solution I adopted was to try to offset the wheels from the vertical axis by their radius. The robot I built does turn in place, almost without moving. There was quite (...) (26 years ago, 3-Mar-99, to lugnet.robotics)

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