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Topic: high strength, positional linear actuator (Read 461 times) previous topic - next topic

slaveboy2000

May 16, 2018, 02:37 am Last Edit: May 17, 2018, 04:19 am by slaveboy2000
I am working on a project that moves a heavy load either forward or backward to a specific location and I am looking for an actuator that would do that. My first thought was a pneumatic or hydraulic cylinder but those require a lot of space and are hard to precisely control. I then thought of a thread system like they have in 3d printers but I can't find a long enough or strong enough thread that would work for my purposes. Are there options I haven't considered or are there ways to better the options I have already thought of?

EDIT:
Sorry for not adding specific definitions, I don't have any actual measurements but looking at it now it seems silly not to just add approximations. To address some of the comments: they need to span about 32 inches and need to pull with about 300 pounds of force. The faster the better, about a half a second to full extension if possible. Thank's to everyone and their suggestions so far, they will be helpful.

EDIT (again):
To address more comments: the actuator would move multiple times in quick succession. The purpose of the project is to move the feet of a walking person to keep them contained in a specific area. It would have to fast enough to fallow a person's feet but strong enough to move the person.

PS. I am not an electrical engineering student but hope to be one someday.

EDIT (hopefully the final one):
Sorry if I was not clear, I am not looking for a specific device but for types of devices that I can research and adapt to my needs. Sorry if my 'noobnes' has caused any annoyance or trouble to people reading this post.

jremington

#1
May 16, 2018, 02:44 am Last Edit: May 16, 2018, 02:45 am by jremington
State how much force is required to move the load and over what distance it is to be moved.

Pololu has a good selection of linear actuators.

MorganS

Firgelli has a big range of reasonably-priced actuators.

For more extreme stuff, look at Motion Systems or Thompson.
"The problem is in the code you didn't post."

MarkT

I am working on a project that moves a heavy load either forward or backward to a specific location and I am looking for an actuator that would do that. My first thought was a pneumatic or hydraulic cylinder but those require a lot of space and are hard to precisely control. I then thought of a thread system like they have in 3d printers but I can't find a long enough or strong enough thread that would work for my purposes. Are there options I haven't considered or are there ways to better the options I have already thought of?
You have used adjectives instead of numbers/units.  Use numbers and units if you want a sensible answer,
your definition of "heavy load" could be orders of magnitude different from mine, for instance.

What force is needed?  What speed is needed?  What accuracy?  All in SI units if possible.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Paul_KD7HB

I have TWO linear actuators that can move 500 lbs, each. 12 inches of movement. They are operated with 120 VAC. I would love to find a home for them. Are they big enough for your project?

Paul

INTP

The 'long and strong' you speak of tells me you're planning on supporting the weight of the whole thing solely on the movement rails.
Wrong approach if weight is an issue. Build a sturdy support track, trolley, rollers, whatever method suits the application so that your motor only has to do work in the horizontal vectors and not constantly grind away at a load on threaded rails. When length gets long, you can start considering belts instead of lengths of threaded rod.

Paul_KD7HB

I am working on a project that moves a heavy load either forward or backward to a specific location and I am looking for an actuator that would do that. My first thought was a pneumatic or hydraulic cylinder but those require a lot of space and are hard to precisely control. I then thought of a thread system like they have in 3d printers but I can't find a long enough or strong enough thread that would work for my purposes. Are there options I haven't considered or are there ways to better the options I have already thought of?

EDIT:
Sorry for not adding specific definitions, I don't have any actual measurements but looking at it now it seems silly not to just add approximations. To address some of the comments: they need to span about 32 inches and need to pull with about 300 pounds of force. The faster the better, about a half a second to full extension if possible. Thank's to everyone and their suggestions so far, they will be helpful.
If you are an industrial engineering student, you just failed the class.

You have defined a SINGLE USE MACHINE. Move something one time and then go to the junk yard.

You may want to define how often the machine will move and how and how fast it returns to the initial conditions.

Paul

jremington

Quote
I don't have any actual measurements
A project design starts with actual data.

Come back when you have accurate, useful information.

Quote
The purpose of the project is to move the feet of a walking person to keep them contained in a specific area.
And you "guess" that this takes 300 pounds force? That would break bones.

INTP

Okay, thanks for the update edit with at least some hint at what it is you are dreaming of in your head.

Now, explain more. Because right now, there is a whole lot of 'that's a really dumb idea if I'm thinking of what I think he's saying' going on.

You want actual people, to stand on this device, and this device is moving the person by moving each foot?
Do you have feet? Have you ever stood before? Walked? Does weight distribution ring any bells?
Is this device on wheels? I'm guessing not because using wheels would make the goal of moving a standing person a quick project in terms of complexity.

So this device is actually making steps. You're not just moving back and forth, you need to lift up to get off the ground. How do you expect the person to know where to put their weight? It doesn't sound like this consideration has crossed your mind yet. Any person capable of knowing when to move their weight to accommodate your deathtrap has the wherewithal to actually just walk.

It literally sounds like you are trying to build something that works out to being equivalent to putting miniature mechanical riding bulls under each foot of a person and the challenge is to predict and stay on the damn thing.

gwareloth

I read your original post yesterday before you added all the edits, and it's only because INTP mentioned that there were edits that I went back and read them.

Etiquette on any forum is to add further info in new posts in the stream so that folk coming back can see the new stuff, since they wouldn't normally know to go back to the top. Apart from that, adding stuff in earlier posts destroys the sense of the thread, since replies between the edits will be to do with the older un-edited opening post, and may be rendered nonsensical after the edits. (That said, at least you marked them as edits and didn't just sneak them in.)


gwareloth

This is a good example of a case where the proverbial picture is worth the proverbial 1000 words. I have no image in my mind of what the heck you're trying to do. Draw a rough sketch of what's in your mind.

The phrase "keep them contained in a specific area" coupled with your forum name makes me wonder what this is all about 8)




gwareloth

Presumably this project is related to your other one, although that one's to do with tracking feet and this one seems to be to do with controlling them.


TomGeorge

Hi,
PLEASE do not go back to your original post and ad edits.
Make new posts each time you want to say something.

By adding EDITS in your first post disjoints the the whole thread.
So any reader who may want to use this thread the find an answer to a similar problem will read conflicting answers and questions.

PLEASE each time you want to say something, say it in a new post.

Thanks..  Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

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