finest servo motor?

Hi all, Just wondering what is the smallest AC and DC servo motor that is available on the market ? What is its corresponding number of count
for the encoder?
I came across the figure 2000 "physical" count/rev for a servo motor. Is this almost the finest encoder available ??
Thanks
John
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The encoder is only one aspect of the resolution of a servo drive system. In any case, 2048 counts is about the maximum practical, and you'd see very few with a greater resolution than this in the commercial or industrial field. Medical and aerospace may see even higher resolutions, and tens of thousands of lines of resolution is theoretically possible.
With quadrature encoding, an encoder with 2048 counts would yield a resolution of 8192 counts per revolution. Whether the rest of the system can handle this resolution is another matter. I doubt most could make use of the granularity.
-- Gordon Robots for Less at Budget Robotics: http://www.budgetrobotics.com/ Author: Robot Builder's Sourcebook & Robot Builder's Bonanza
blackmonkey2046 wrote:

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On Mon, 15 Sep 2003 12:18:23 -0700, Gordon McComb wrote:

Higher encoder resolution is better for the servo controller, so that the velocity feed back term (damping) is less grainy. There are techniques for smoothing the feedback (filtering and 1/t for example) but they all involve compromises for a high performance system, better to have high encoder resolution.
That said, higher resolution encoders are more delicate...
Peter Wallace

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