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DPRG: Diffrent terrains for navigation

Subject: DPRG: Diffrent terrains for navigation
From: John Alway jalway at icsi.net
Date: Thu Aug 19 16:14:40 CDT 1999


   Have you looked into rotational accelerometers?   Amp makes piezoelectric
accelerometers.  I received a sample chip when I requested info on piezo
film.  It's a small surface mount chip, about the size of an LM386.   There
is no price given, but they claim it's cheap.   Just a thought.


- -----Original Message-----
>From: Matt Minnis <mminnis at prefres.com>
To: dprglist at dprg.org <dprglist at dprg.org>
Date: Thursday, August 19, 1999 4:48 PM
Subject: Re: DPRG: Diffrent terrains for navigation

>I use a six wheeled design.
>They are arranged in more of a hexagon than a rectangle.
>Here is the link to my robot so you can see for yourself:
>I have since placed scotch tape around the rear wheels.  This has helped
>My father suggested since the rear wheels are in a basic suspension, raise
>them up so that they are only used when the robot is rolling over
>something.  I have not tried this yet.  I have to shift some weight to do
>this right.
>I am going to get a vector compass from Jameco soon, and I am concidering a
>trailing wheel with an encoder.
>Yes the wheels skid in every turn.  They are the spongey model airplane
>wheels and have a high friction to them.  The upside is they get great
>traction.  :)  However this is the result.  :(
>The number of clicks may be off by a couple but it is off by a large margin
>in degrees, perhaps as many as 45.
>At 12:23 PM 8/19/99 -0500, you wrote:
>>Howdy Matt,
>>you wrote:
>> > I was wondering how the rest of you handle wheel slippage and other
>> > on diffrent terrains.
>> > Like if I am on carpet it turns vastly diffrent than on linoleum, which
>> > also diffrent than on hardwood flooring.
>> > On each diffrent surface, I turn a diffrent amount for the same # of
>> > encoder clicks.
>>My current 'bot on hardwood vs. carpet maybe a little different, but
>>hardwood vs. linoleum are probably identical.
>>What is the geometry of your platform?
>>How are you steering?
>>Do the wheels skid sideways in a normal turn?
>>Are you certain you turn the same number of clicks, including overshoot,
>>(which changes with friction) at the end of the turn?
>Preferred Resources          (314) 567-7600 phone
>701 Emerson rd.              (314) 993-6699 fax
>Suite 475
>St. Louis, MO


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