DPRG mailing list archives: [DPRG] Absolute reference for angular position

Tue May 27 15:13:47 CDT 2008

Sluggy!

 > All the solutions given up to this point seem to be
 > towards the robot being self-calibrating. The only
 > problem with any of these is that it's adding another
 > sensor, one that is intentionally narrow in focus,
 > with all the problems that represents.

Right now that's how I'm planning to use it, but a sonar array or even a single 
unit would also be useful for general purpose obstacle avoidance or targeting, 
once I get up to those lofty levels.

 > If this measurement is for one time (or even
 > occasional) manual calibration, how about a laser
 > pointer attached to the chassis and pointed to a spot
 > on the wall. Mark that spot. Rotate the robot under
 > program control to what it thinks is 360 degrees.
 > Using a high tech ruler, measure the error by where
 > the laser ended up pointing. Repeat many times,
 > perhaps averaging the results. Adjust the count in the
 > software.

That sounds like the simplest way to achieve what I want to do.  I have lots of 
lasers of all sizes laying around.

Thanks,

Dale Wheat

(972) 486-1317
(877) DALE WHEAT
http://dalewheat.com

Sluggy! wrote:
> All the solutions given up to this point seem to be
> towards the robot being self-calibrating. The only
> problem with any of these is that it's adding another
> sensor, one that is intentionally narrow in focus,
> with all the problems that represents.
> 
> If this measurement is for one time (or even
> occasional) manual calibration, how about a laser
> pointer attached to the chassis and pointed to a spot
> on the wall. Mark that spot. Rotate the robot under
> program control to what it thinks is 360 degrees.
> Using a high tech ruler, measure the error by where
> the laser ended up pointing. Repeat many times,
> perhaps averaging the results. Adjust the count in the
> software.
> 
> Sluggy!
> 
> ---
> 
> "The idea that unicycling is intrinsically funny does not explain the findings." Professor Sam Shuster.
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