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Very Fast Linear Actuator with potentiometer?

I'm trying to create controllable agile linear motion.

The idea was to use a low force high speed linear actuator with a potentiometer in combination with an H-Bridge and a picaxe to control to linear distance via a laptop. The problem seems to be finding the right linear actuator.

Most of the actuators I'm finding that have built in lineat pots are very slow...anyone know where I can find actuator to fit my needs...or potentially another mechanical solution that might satisfy my requirements.

Max Linear Resistance: 10-15lbs

Ideal Stroke Speed: 20+inches per second.


Any help?

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that comercial CNC machines move at 700 ipm and from what I have heard pushing 1000 ipm. Hobby machines can readily move at 100 ipm. I would imagine the low end ones are still using threaded rod and some kind of nut, be it delrin or otherwise.

Progressive Automations sells a high speed tube linear actuator with a speed of 10.6 inches per second. Granted the load capacity is 11lbs, at which point the speed is less...

I would assume that a stronger/faster motor could provide a increase in speed, however I agree that on these the nut is most likely delrin or some other polymer...

I ball nut would allow for faster travel, but its more expensive...like something from Nook Industries.

Linear actuators are not really known for their speed, instead they are designed for power. I can't think of anything I have seen that comes anywhere close to 20"/sec. That is REALLY fast, dude. At those speeds, I think you may want to start looking at pnemumatic cylinders instead. The other option may be a belt around 2 sprockets to translate the rotation of a motor into the linear movement you want. A flatbed scanner would have this belt/pulley set-up inside.

If nothing else, you can do some math here... Any kind of threaded rod will have a certain TPI (threads per inch) and thus you can easily calculate how the RPM of your motor will translate to the speed of the nut flying down the rod. (if you end up making your own)

I cant recall an instance of being able to digitally control the extension of a pnuematic cylinder...its either fully extended or fully collapsed.

a standard nut on a piece of threaded rod will generate some serious heat when moving at those speeds. I've heard of ball nut actuators or ball screw actuators....just didnt know if they are available for robot applications.

At this point its looking like creating my own might be my only "economical" option.

I though I might be able to take one of the linear actuators from the "Components" section and re-gear the box to get what I want.

for example: http://www.pololu.com/catalog/product/2319

How easy is it to regear these things? Or swap out for a faster/stronger motor?

you gave us force and velocity, but, left out stroke :)

Stroke actually doesnt matter...

Usually actuators are available in several stroke lengths, its really the speed and measurement that I'm concerned with...

...one problem at a time i guess.