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Subject: 
Re: Two more for the wish list
Newsgroups: 
lugnet.robotics
Date: 
Sun, 28 Jan 2001 20:27:44 GMT
Viewed: 
727 times
  
A few months ago I built a model of two synchronized metering pumps, one for
nitro-goo and one for glycerine-goo.  The idea was to have both pumps
synchronized.  I did it with a differential and a rotation sensor to mark
the difference and a controller to slow down the faster pump.  So I could
watch the exact position of the differential body and watch the *zero* count
simultaneously (ranging from -1 to +1).  I noticed the missed counts, where
the body would shift by 20 or so degrees while the 'count' centered at zero.

I attributed the missed counts to a control system like OnFwd(10) Wait(10),
that caused a lot of vibration.  On the average, I got about 10 minutes of
ops between missed counts.  OK for keeping a robot in a straight line but
not good enought to compound nitro-glycerine :-).

Regards, Jerry

In lugnet.robotics, sjbaker1@airmail.net writes:
Jerry Kalpin wrote:

Matthias, this is easy to do without a new part.  You use a normal
differential, put one shaft in one side, the other shaft (but reversed) in
the other and connect the rotation sensor to the output.  You get a positive
count if the right wheel is going faster and a negative count if slower.
However, a differential with a reverse feature on one input would be great.

Yes - but if you've been following the discussions about dropped counts,
you'll know that the standard rotation sensor is pretty inaccurate when
you set it up like that.  It likes nice *fast* rotation rates.



Message is in Reply To:
  Re: Two more for the wish list
 
(...) Yes - but if you've been following the discussions about dropped counts, you'll know that the standard rotation sensor is pretty inaccurate when you set it up like that. It likes nice *fast* rotation rates. (24 years ago, 28-Jan-01, to lugnet.robotics)

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