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What actuator to accelerate/position small load fast and accurate

Posted by Genesys 
What actuator to accelerate/position small load fast and accurate
April 22, 2019 09:54AM
I want to position a small load (aprox. 10g) within a quite small envelope (maximally 1x1cm) in the XY plane. Important aspects are accuracy, repeatability and most importantly speed/acceleration. Think having the object trace a star shape as quickly and as accurately as possible.

What kind of actuator is well suited for this?
I understand that a good answer would need more info on the actual specs - but there are no specs yet. As a baseline, what would be better suited than two nema 17s with lead screws?
Re: What actuator to accelerate/position small load fast and accurate
April 22, 2019 11:10AM
If I were looking to move something that light both accurately and very very fast I would look at ways of using the voice-coil head positioning system from a couple of hard disk drives. If feedback could be worked out the existing electronics may even be adaptable. Although I have never had occasion to look, somebody in the maker/academic/geek communities must have used these for a fast positioning system.

Mike
VDX
Re: What actuator to accelerate/position small load fast and accurate
April 22, 2019 01:42PM
... how fast?

When developing micropositoners with accuracies in the sub-microns and traveling ranges of up to some ten Millimeters, I've used piezo-drives or self developed "voice-coil" positioners with FerroFluid on Neodym-magnets as "stick'n'slip-free" bearings ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: What actuator to accelerate/position small load fast and accurate
April 23, 2019 05:18AM
How could I source such closed loop positioners on the cheap? I know that harddrives have them, but as I understand them, the platter is part of the closed loop and actually needs to spin and data being read for the accurate positioning to work, so that makes them unusable to use for anything else other than fast oscillation
VDX
Re: What actuator to accelerate/position small load fast and accurate
April 23, 2019 05:41AM
... for this my question "how fast?" -- expand it with "how much torque?"

Depending on needed force (torque) you don't need close-loop -- otherwise, with this small moving ranges as some ten Millimeters, you can use a camera for position feedback ... I've used a "naked" camera chip and two optical grids together with an image-recognition software to detect moving with accuracies in the ten Nanometers ... but this was more for a scientific "studies" than for practical usability.

"on the cheap" is another hurdle - my piezo-drives were in the range of 60USD or 400USD, so not this cheap ... the coils for the magnetic positioners were too in the range of 60 to 100€ ...

So better sketch your basic needs -- moving range, accuracy, speed, cost, ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
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