Subject:
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Re: dc motor blues
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 10 Apr 1998 11:28:39 GMT
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Original-From:
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Fred G. Martin <fredm@media.mit.!avoidspam!edu>
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Viewed:
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1147 times
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yup, here's what's going on. the motor percent argument controls the
POWER, not the speed. if the motor is essentially unloaded, it will
run at nearly full speed even at a low power percentage.
if you build a gear train that makes the motor do some real work (like
carry around the handy board), then you should see a pronounced speed
difference as a result of the different power levels.
fred
In your message you said:
> After driving all my robots with step motors, I finally decided to try
> driving one with DC motors. I got a couple of the lego gearmotors, and
> mounted them on my robot with belts driving the wheels at a reduction ratio
> of about 1.5:1, and have been doing some experimenting with the different
> speeds.
> I am very surprised at the lack of change between speed 11 (which is the
> slowest speed that will actually make the motor turn), and speed 100. As
> near as I can tell there is an 18 rpm difference between speed 11 and speed
> 100. The difference is so small that I can't see any difference when I run
> my robot across the floor at any speed. (given that speed 11 results in
> 183 rpm at the wheel, that is less than a 1% change!)
> Has this been the case with any of you? Am I doing something wrong? I
> don't want to have to go back to step motors! Please email me with your
> experiences!
>
> Note: I am using IC 3.2, but I don't know if the new 'smooth pwm routines'
> are in there. Anybody know how I can tell? and if they're not, how do I
> implement them?
>
> thanks for any insight you can give me.
> -patrick
>
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Message is in Reply To:
 | | dc motor blues
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| After driving all my robots with step motors, I finally decided to try driving one with DC motors. I got a couple of the lego gearmotors, and mounted them on my robot with belts driving the wheels at a reduction ratio of about 1.5:1, and have been (...) (26 years ago, 10-Apr-98, to lugnet.robotics.handyboard)
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