beefy linear activator

Geez, sounds like hydraulics and a sensitive feedback system to me.

This is about the simplest and least expensive option if all he needs is the actuator without any guides...

There are probably hundreds of variations on this sort of thing from a dozen mfrs if the load needs to be guided...

Plenty of other options as well, depending on the exact requirements.

Ned Simmons

That's about 1.4 degrees on a Bridgeport knee crank. Seems like a linear encoder and servo should get you something like that, assuming you're not deflecting it with a varying load.

Levers are know to do this. While increasing force, they also can increase accuracy.

Nick

They sure don't make scientists like they used to! Problems like this are what scientists used to solve. Bugs

If it's not moving very far or fast why not just counterbalance it with a weight or gas springs and use a "normal" strength actuator setup? Certainly cheaper than a beefy actuator.

Pete C.

Looks like Ned had some good solutions. Out of curiosity, what sort of speed does your guy need?

I don't believe speed is an issue. However, none of the activators I've seen so far including the ones Ned pointed out have optical encoder outputs which is a requirement for his system.

GWE

The Intelligent Actuator unit is servo driven, so it does have integral encoder feedback. It would be simple enough to add a linear encoder to a system using the Haydon stepper actuator.

From what you've said so far, this doesn't appear to be a difficult application, but more detail is required.

-Is the 10 micron number truly a precision spec, or is it accuracy or resolution? (accuracy = $$$$, precision = $$, resolution = $)

-Is the load adequately guided and only acutator is needed, or is load support and guiding also required?

-What's controlling the position? Closed loop? What's the position feedback for?

Ned Simmons

Check these guys:

I'd think with heavy loading it would be best to have the actuator and resolver separate, so the resolver measures actual load position without error from a lead screw, backlash and strain in gears, strain and deflection in load-bearing members, etc.

Another possibility might be these instruments from Fowler:

Movement on that scale makes me think of piezoelectric pushers. The simple ones are made in the form of washers stacked on a bolt. When you apply 1kV, the bolt stretches. Plenty of force. They also make inchworm type pushers that grab and push alternately. Sort of like a stepper, I guess.

When I was at Lockheed I did the electronics for a system that (the physicists claimed) kept two mirrors parallel to within 50 Angstroms. I suspect a little optimism in this number, but we were definitely controlling to some small fraction of a wavelength of visible light. Closed loop system via optical sensors.

I came across these folks recently, they have motors listed with 50mm of travel:

Grant Erw> I know a guy who has a very unusual requirement. He needs to move

I talked to my brother. They are building a table with two large brass rocket nozzles pointing at each other (sort of like 2 Bunsen burners) and mounting laser optical send/receive units on either side of the gap between the burners, not mounted to the table. They need to be able to move the lasers relative to the motor axis and it's a lot easier to move the motors than the lasers. It's very cool, the way they take flame profiling data, wish I could get a few hours in that lab (in the astrophysics building @ USC) to profile a few different Ron Reil type aspirated pipe burners, would settle a bunch of arguments right quick.

Anyway, he thinks what Ned sent along earlier can be made to work, so thanks all.

Grant

D> >

He can't use separate optical encoders? He knows a _machinist_ and he can't figure out how to mount separate optical encoders?

Hmm.

Try these guys.

Pete Keillor

There are instruments in use in high energy physics that needs every bit. Think optical telescopes - the tuning one with a hundred or so mirrors - We all expect perfect pictures from these big scopes - remember the Hubble issue ? Precision is one thing, accuracy is another. Some work isn't with a hatchet, and survey chain!

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member

Ned Simm> >