Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!noc.near.net!howland.reston.ans.net!usc!cs.utexas.edu!csc.ti.com!tilde.csc.ti.com!mksol!strohm
From: strohm@mksol.dseg.ti.com (john r strohm)
Subject: Re: Some motor ideas, and related: Suggestions wanted.
Message-ID: <1993Apr21.233746.8095@mksol.dseg.ti.com>
Organization: Texas Instruments, Inc
References: <1r4ce3INN3cn@snoopy.cis.ufl.edu>
Date: Wed, 21 Apr 1993 23:37:46 GMT
Lines: 33

In article <1r4ce3INN3cn@snoopy.cis.ufl.edu> jrw@elm.circa.ufl.edu (James Wucher) writes:
>Greetings,
>   I am an EE grad student thinking of building a pet project.  Actually, 
>I saw someone who had done a similar idea, and was thinking of building 
>the device to my own specs instead of theirs.  Basically what I am building
>is a roving tractored vehicle weighing about 20-25 lbs.  I plan to power
>it with one (or maybe two) 6V lantern batteries.  It only has to run 
>continuously for about an hour, so effieciency is not a great factor.  
>Any ideas on the type of dc motor to use (stepper, etc.) as well as some
>ideas on how to control the motors would be appreciated.  Please be aware
>that if this sounds like a strange question from an EE (like one I should
>already know the answer to) then consider that my area of interest is 
>control systems, and this is my first  real construction project of any
>magnitude.  Any help would be appreciated.  Thanks.
>

Suggestion: Unless you really want to learn a whole lot about mechanical
fabrication, consider trying to find something that can EASILY be adapted
for mobile robotics.  Three platforms are readily available that I know of:

Radio Shack used to make a radio-controlled tank model that used independent
small DC motors to drive the treads, one motor each for left and right.

Kyosho makes the Blizzard tractor, which was specifically designed for radio
control with a two-channel radio.  Generating R/C PWM signals is trivial for
a modern microcomputer like the 68HC11.

There is a child's riding toy, the B.O.S.S. (Battery Operated Spin System).
It has six wheels, three on a side, chain-ganged together.  Each side is
independently driven by a separate motor.  Existing control is a joystick
that closes switches.  Adapting this to PWM with a large power MOSFET and
using a high-current relay to reverse the polarity to the motor is quite
simple; a friend of mine did it for his homebrew robot platform.
