Alt-BEAM Archive
Message #04882
To: beam@sgiblab.sgi.com, James Anderson anderson@cfht.hawaii.edu
From: Bruce Robinson Bruce_Robinson@bc.sympatico.ca
Date: Sat, 26 Jun 1999 16:49:38 -0700
Subject: [alt-beam] Re: Photopopper problems
James Anderson wrote:
>
> I finished my first photovore yesterday, ... the problem I'm
> having is that [the wheels] only turn when not touching the ground ...
and JVernonM wrote:
> The problem you are having is with the torque strength of pager motors,
> i.e., they have none. ... In your set up, you are better off to remove
> the wheels and run the bot on the motor shafts.
and James Wilson wrote:
1
> My advice is to loose the wheels and use shrink tube on the shafts ...
This advice is exactly right. With large diameter wheels driven directly
from the motor, your torque demand goes way up. Running directly on the
motor shafts (covered with heat shrink tubing for traction) should solve
your problem. The only difficulty is if you don't have enough ground
clearance to do this.
An equivalent method is to use your hard rubber wheels as "idlers".
Mount them on axles so they spin freely, then place your motor shafts so
they run against the surface of the wheels. Steve Bolt's robot,
"Willie", is an example of this method (even though he isn't a
photovore). Take a look at:
http://www.xs4all.nl/~sbolt/e-andere_robots.html
To see the motor-wheel arrangement. Except for a small friction loss,
this is exactly the same as running your motor shafts directly on the
ground. And it doesn't matter what size your wheels are -- they are just
idlers.
Take care,
Bruce
------------------------------------------------------------------------
eGroups.com home: http://www.egroups.com/group/alt-beam
http://www.egroups.com
- Simplifying group communications
Home