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From: roger034@gold.tc.umn.edu (Brynn Rogers)
Subject: Re: Help - DC Motor Selection
Message-ID: <Cv82oG.DrE@news.cis.umn.edu>
Keywords: DC Motor
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References: <1994Aug26.141509.20546@mksol.dseg.ti.com>
Date: Sun, 28 Aug 1994 01:49:24 GMT
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In article <1994Aug26.141509.20546@mksol.dseg.ti.com>,
Norman W Cramer <cramer@mksol.dseg.ti.com> wrote:
>I am in the process of designing an mobile robot.  The robot will use 
>two motors for differential drive.  I need some help to determine the 
>motor specifications.  The robot should weigh less than 50 lb. and will 
>be used in an outdoor environment (My yard).  The terrain is not very 
>steep or rough.  The drive train has a 3.4:1 reduction so far (more can 
>be added with the motors), and the wheels are 8 in. in diameter.  What 
>process can I follow to determine the ratings for my motors.  I know how 
>to determine the RPM required but am having trouble with the torque 
>specifications.  
>
>I also need a source for inexpensive motors and reduction gears.  I 
>would like to get the lowest cost drive system that will do the job.
>
>Thanks,
>Norm
>
>cramer@dseg.ti.com


   I have found from building a four wheel drive robot that uses skid-steer
(forward on the left two motors, backwards on the right two spins the
robot in place (to the right ))  The torque required to skid steer is
at least 10 times the amount of torque needed to move.  
   If you use some sort of steerable wheels you can get away with much
smaller motors.

   How do you plan to steer?

--
Brynn Rogers                                   roger034@gold.tc.umn.edu
-------------   Space,  the final frontier.   -------------------------
Autonomous robots get my interest.     Embedded systems pay my mortgage.
