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[DPRG] Absolute reference for angular position
Subject: [DPRG] Absolute reference for angular position
From: Dale Wheat
dale at dalewheat.com
Date: Tue May 27 15:09:51 CDT 2008
David,
> However, it sounds from the following like you are looking for a
> way for the robot to calibrate itself. Yes?
Ultimately, yes. In the short term, I would assist somewhat. :)
> Our friends from the University of Michigan suggest that you can do
> this with a single sonar by placing the robot at a known location in
> a corner. The robot uses the sonar to measure the distance to the
> two corner walls by measuring the distance to one, rotating 90
> degrees, and measuring the distance to the other one. Then run
> your calibration procedure, and measure the distances again. This
> gives both location and theta error, and the robot should be able
> to calibrate itself. That would be pretty cool, and something
> that would be easy to run each time you change wheels, or take
> the robot apart and put it back together.
Is that described in more detail in the "Where Am I?" paper? I have enough
sonar units (i.e., 1) for that procedure.
> I've found that a small laser pointed accurately aligned to the
> robot's main fore/aft axis is a mighty handy thing to have, both
> for calibration and for general running. It's difficult otherwise
> to tell exactly "where the robot is pointed." Alternately some sort
> of boresight that can be sighted along for aligning the robot with
> a particular course, like sight marks on a telescope, might be
> helpful.
Something I and Dr. Evil both plan to include in the near future, if it's not
too much to ask.
> Dale, how about "All of the Above?"
Probably the best suggestion so far!
Thanks,
Dale Wheat
(972) 486-1317
(877) DALE WHEAT
http://dalewheat.com
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