Subject:
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Re: Precise turns of any angle!
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 12 Jan 2002 20:52:21 GMT
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Viewed:
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2493 times
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In lugnet.robotics, sjbaker1@airmail.net writes:
> "Brian H. Nielsen" wrote:
>
> > The robot has a top mounted cane which rotates 360 degrees and about
> > 2.75" off the floor. The cane is on large 56 tooth turntable and linked
> > to a rotation sensor in a 7:1 gear ratio to increase the sensitivity of
> > the rotation sensor to 112 clicks per full rotation of the cane. The
> > turntable is mounted over the robot's center of rotation. The assembly
> > is driven via a motor and pulley setup, allowing the motor to run
> > continuously without fear of burning out when the cane is in contact
> > with an obstacle.
> >
> > The basic theory of operation is that the rotation sensor tracks the
> > orientation of the cane and when the cane is in contact with an object
> > it stops rotating and we have a directional reference against which to
> > make course corrections.
>
> The trouble is that the rotation sensor drops counts when you run it
> at low speeds - especially if it's reversing direction frequently.
>
> You can read about my experiments that prove that fact here:
>
> http://www.sjbaker.org/steve/lego/rotation_sensor.html
I've done your experiment and I won't dispute that the rotation sensor
drops counts. However, that only impacts the wall following application
only to the extent that it would require periodically going through the
initialization function which calculates the distance the robot currently is
from the wall.
The application of making precise turns is completely unaffected since it
doesn't matter what the current value "X" is to start a turn, only that we
pivot until the counter reads "X+Y". At pivot speeds the rotation counter
is turning neither too slow nor too fast.
Brian H. Nielsen
LUGNET Member #108
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Message is in Reply To:
 | | Re: Precise turns of any angle!
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| (...) The trouble is that the rotation sensor drops counts when you run it at low speeds - especially if it's reversing direction frequently. You can read about my experiments that prove that fact here: (URL) told that you get much better results (...) (23 years ago, 12-Jan-02, to lugnet.robotics)
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