[Robotgroup] Drive a Droid proposal... How to detect the "fence"?

[Doug Evans]

Alex,

Slightly Off topic, but why is this difficult?

Once you have the encoders, and you have accurately calibrated your
wheelbase and your wheel diameter, this is just a little bit of
trigonometry.

-de


-----Original Message-----
From: robotgroup-bounces at puremagic.com
[mailto:robotgroup-bounces at puremagic.com] On Behalf Of Alex Iles
Sent: Tuesday, July 08, 2008 3:38 PM
To: The Robot Group Mailing List
Subject: Re: [Robotgroup] Drive a Droid proposal... How to detect the
"fence"?

> Clendon Gibson wrote:
>  > If you are good with geometry, then you can put encoders on
>  > the wheels and calculate your position by dead reckoning.
>
> Friction errors accumulate as the wheels move over the surface and slide
> on occasion. You would have to rely on external, calibrations and
> corrections for any deviation caused by accumulated error. The amount of
> calibrations would depend on the surface, the wheels and the number of
> events that could cause slip (i.e. hard starts and stops, turns etc).
>

It's also very difficult to dead reckon wheel progression through turns...

-ai

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