Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!cs.utexas.edu!howland.reston.ans.net!europa.eng.gtefsd.com!library.ucla.edu!news.ucdavis.edu!csus.edu!netcom.com!nstn
From: nstn@netcom.com (Nathan Stratton)
Subject: steering system for mobil robot
Message-ID: <nstnCoJGzn.6As@netcom.com>
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date: Wed, 20 Apr 1994 03:42:59 GMT
Lines: 42

     Well I finished the state science fair and did not even
place, some of the judges said that my robot should be in
engineering and not in computer science because it is not
software. i tried to point out that this is the category they
said I should be in and computer science is more then software. I
had a working mobil robot in front of them, I domoed it on a
brick so if would not move off the table and I also had a video
that showed my programming a course and the robot repeating the
course without running into object so that they could see that
the sonar worked.
     I am glad I did not build it for the science fair, I would
like to fix some problems with this robot and ad telepresence and
I wanted to get some feedback for Comp.Robotics. Problem number
one is the steering, the robot moves using a front wheel drive
and steering mechanism. I am now using a encoder, and having the
robot turn right of left an number of ticks. Some of the problems
are:

1. The robot is not able to correct itself, when it looses ticks
the error just increases.
2. If the computer crashes or there is an error in the program
the steering shaft just spins around and rips the encoder, drive
motor and steering motors wires out of there connectors.
3. Getting the robot to move in a straight line, the robot drifts
to the right or the left no matter what I do. 

     I was thinking about getting rid of the steering encoder and
just using reed switches and a magnet mounted on the drive shaft.
The robot would have a fixed number of steering positions This
would be self correcting because the steering shaft would move
until the switch was closed by the magnet. I was then mount two
kill switches so if the steering shaft moved to far it would cut
power to the motor.
     So if you have any comments or suggestions let me know what
you think. Thanks so much for the help and ideas,


-- 
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 | Nathan Stratton              Washington and Lee High School Junior        | 
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