<div dir="ltr">Sometimes dithering (ie. actually adding noise) is a good way to overcome stiction.<br></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Oct 18, 2018 at 1:01 PM Marshland Engineering <<a href="mailto:marshland@marshland.co.nz">marshland@marshland.co.nz</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Had a flurry of replies.<br>
<br>
Here is the setup.<br>
<br>
<a href="http://www.marshland.co.nz/ftp/CAM/Jig.JPG" rel="noreferrer" target="_blank">http://www.marshland.co.nz/ftp/CAM/Jig.JPG</a><br>
<br>
The data<br>
<br>
<a href="http://www.marshland.co.nz/ftp/CAM/Plots.jpg" rel="noreferrer" target="_blank">http://www.marshland.co.nz/ftp/CAM/Plots.jpg</a><br>
<br>
<br>
A very small step in measuring makes a huge step in the velocity graph and a<br>
similar one in the acceleration.<br>
<br>
Since posting, I did think about letting the cam run through several cycles<br>
and the averaging the new data. Probably best to do that first. It is the<br>
stiction that is the probable issue with the linear encoder. I am measuring to<br>
1 micron.<br>
<br>
Maybe best to not average the raw data but average the velocity.  <br>
<br>
Cheers Wallace<br>
<br>
<br>
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