|
[DPRG] Borenstein squares
Subject: [DPRG] Borenstein squares
From: Randy M. Dumse
rmd at newmicros.com
Date: Wed May 21 11:22:39 CDT 2008
> So is this doing an in-place turn? i.e. one wheel going
> forwards while the other goes backwards? Or are both wheels
> going forward differing amounts?
Yes, both.
When we test out turn, we do turn in place, one forward and one
back. But we also did holding of one wheel still and rotating
only the outer one. We did lots of rotation of the body by hand
and just letting the wheels follow. Seemed everything we tried
gave us different numbers, and it varied based on surfaces most
of all.
As I look back on it, it probably means we had a slipping shaft
to the motor. I had not suspected mechanical linkage failure.
Well, there's only limited presence you can have working on a
video link over the internet with students doing the physical
efforts on the other end.
> Differential steering will most likely put some sideways
> pressure on the wheels. If you're using omni wheels then you
> could be getting some sideways movement, which your odometry
> doesn't account for.
The omniwheel is being used as a caster. It is just the rear
wheel of the tripod. The front end used to be the backend of a
Traxxas Emaxx. However it had two differentials up front, so the
wheels could be driven differentially. We ran two swiss motors
through the differentials to the two (now front) wheels.
Modifications done in the last two days have eliminated the
differntials. So now we have the two swiss motors directly in
line with the wheel drive shafts. Hopefully this will get our
speed up 3x or 6x (never got a straight answer on the gear
ration through the Emaxx transmissions). We had enough torque
already. (I was told, anyway. We'll see when we encounter a curb
with the new configuration.)
The other student than came down is planning on entering this
chassis at the RoboGames, RoboMagellan, in San Fransisco in
June. I'm not sure if it will be ready. But you know students.
Hope springs eternal.
Randy
More information about the DPRG mailing list
|
