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Linear Actuators VS Pneumatics


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#26 Smithy

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Posted 24 June 2009 - 11:16 PM

I never realy thought how fast the lego pneumatics could be untill I saw the pneumatic enginesthat are reving over 1,500 rpm.

Unless I'm mistaken, the last Lego pneumatics set was the Mobile Crane - 8421 in 2005.  Any model since has either had the actuators or gears.

#27 Blakbird

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Posted 25 June 2009 - 12:49 AM

View PostSmithy, on Jun 24 2009, 03:16 PM, said:

I never realy thought how fast the lego pneumatics could be untill I saw the pneumatic enginesthat are reving over 1,500 rpm.

Unless I'm mistaken, the last Lego pneumatics set was the Mobile Crane - 8421 in 2005.  Any model since has either had the actuators or gears.

8285 in 2006 had minimal pneumatics.
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#28 Milan

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Posted 25 June 2009 - 01:36 PM

View PostSmithy, on Jun 25 2009, 01:16 AM, said:

I never realy thought how fast the lego pneumatics could be untill I saw the pneumatic enginesthat are reving over 1,500 rpm.


actually, pneumatics can be even faster than that.  LPEs can achieve much more RPM, up to 6000,
if air is delivered with big compressor, or plastic bottles with (very) compressed air.

goal is to create LPE which is working steady and smoothly in both low and high RPM, and of course high RPM.
very hard work, since those guys are working on it for a few years now.
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#29 5150 Lego

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Posted 25 June 2009 - 04:13 PM

View PostSmithy, on Jun 25 2009, 12:16 AM, said:

I never realy thought how fast the lego pneumatics could be untill I saw the pneumatic enginesthat are reving over 1,500 rpm.

WOW!!! :oh:  Those are incredible!! I've never seen those before. Very impressive!
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#30 Burf2000

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Posted 09 July 2009 - 12:08 PM

I would of thought the pneumatics would be stronger.  You can get some real pressure on them, some of the engines they have on youtube are amazing.  I dont have a actuator yet but i think I got and buy one off bricklink to run a strength test

#31 Milan

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Posted 09 July 2009 - 01:23 PM

You do not have to buy it just to see which one is stronger, you have numerous tests on net,

actuators are much stronger, more precise and they hold position in any point.

strength of actuator is about 3.5 kg, when internal clutch starts to slip"



pneumatics can lift about 1.5 kg
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#32 Burf2000

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Posted 09 July 2009 - 01:35 PM

View PostMilan, on Jul 9 2009, 02:23 PM, said:

You do not have to buy it just to see which one is stronger, you have numerous tests on net,

actuators are much stronger, more precise and they hold position in any point.

strength of actuator is about 3.5 kg, when internal clutch starts to slip"



pneumatics can lift about 1.5 kg

Thanks for the info, I would of thought that pneumatics could do more than 1.5kg>  is that when it leaks?

#33 Milan

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Posted 09 July 2009 - 01:55 PM

it is when hoses burst off the cylinder. The older the cylinder, the more air will leak out of it when under load.

In pneumatic engines (LPE) they tied up the hoses to cylinders in order to withstand the pressure. Someones use non-lego hoses which grip much better
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#34 CP5670

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Posted 09 July 2009 - 06:17 PM

View PostMilan, on Jul 9 2009, 08:23 AM, said:

You do not have to buy it just to see which one is stronger, you have numerous tests on net,

actuators are much stronger, more precise and they hold position in any point.

strength of actuator is about 3.5 kg, when internal clutch starts to slip"



pneumatics can lift about 1.5 kg

Interesting video. It looks like the LAs can produce quite a lot of force. In practice though, their full power can only be realized if the motor is attached to them directly without any external gearing, which becomes bulky and expensive. If you run multiple LAs off one motor and use geartrains to hook them up, as most of the official Lego models have done, then they would be much less powerful.

Edited by CP5670, 09 July 2009 - 06:18 PM.


#35 Burf2000

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Posted 09 July 2009 - 06:29 PM

Has anyone got a video of pneumatics and there force?

#36 allanp

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Posted 12 July 2009 - 10:49 AM

Quote

As someone else said, pneumatics are just way cooler than a mechanical linear actuator.

Agreed. They are just sooo cool   :wub:  

Quote

But the facts that seals wear out over time, manufacture is most likely more expensive, and that valves and hoses are required to make up a complete system, makes the mechanical actuator a more reasonable choice, I guess.

Ah yes but when you consider the amount of peices required for an LA (gear trains, possibly motors, etc) I think pneumatics work out cheaper, especially if you want to use more than one.

Quote

I own several of the LEGO pneumatic sets, and have wowed friends and coworkers with the amazing functionality. I somehow doubt I'd get the same reaction from a mechanically driven system.

This is very true. Many people seem to be impressed with the pneumatics whilst LAs just seem a little boring compared to pneumatics (even more so when using a motor/compessor pump)

Quote

There's just something awesome about all those hoses everywhere, flipping the little selector valves, and watching the model operate just like the real thing.

And isn't that what Technic is supposed to be all about, working like the real thing!



View Post5150 Lego, on Jun 25 2009, 05:13 PM, said:

WOW!!! :oh:  Those are incredible!! I've never seen those before. Very impressive!

Yeah, imagine trying to do that with LA's :laugh:


View Post5150 Lego, on Jun 25 2009, 05:13 PM, said:

WOW!!! :oh:  Those are incredible!! I've never seen those before. Very impressive!

Yeah, imagine trying to do that with LA's  :laugh:


View Postburf2000, on Jul 9 2009, 07:29 PM, said:

Has anyone got a video of pneumatics and there force?

No but i'm sure they can lift more than 1.5 kgs. Iv'e done so in the past. Iv'e measured the pressure and using only technic parts (no third party elements) in a fairly typical setup, you can easily get pressures of over 30 psi (60 is about the limit :look:) The surface area of which this pressure acts (depending on weather it's going in or out) is approximately 3/8 inch square. This gives you a force equilent of over 5 kgs operating at 30psi, which sounds about right.


View Postburf2000, on Jul 9 2009, 07:29 PM, said:

Has anyone got a video of pneumatics and there force?

I havent seen a video but i'm sure they can lift more than 1.5 kgs as I have done so in the past. Iv'e measure the pressure and using only lego in a typical set up it's quite easy go get 30psi of pressure (60 seems to be about the limit!) The surface upon which this pressre acts within a pneumatic cylinder (depending on which way it's going) is about 3/8 of an inch. The gives the equivolent force of about 5 kgs, which seems to be about right.


View Postburf2000, on Jul 9 2009, 07:29 PM, said:

Has anyone got a video of pneumatics and there force?

I havent seen a video but i'm sure they can lift more than 1.5 kgs as I have done so in the past. Iv'e measure the pressure and using only lego in a typical set up it's quite easy go get 30psi of pressure (60 seems to be about the limit!) The surface upon which this pressre acts within a pneumatic cylinder (depending on which way it's going) is about 3/8 of an inch. The gives the equivolent force of about 5 kgs, which seems to be about right.




Ah poo! Sorry for posting the same think three times  :cry_sad:



Quote

I think that mayor problem with pneumatic is that they come in only 2 sizes (3 with very old one), none which is usable in even slight bigger working model.
I have always wanted long and thin cylinder in my excavators or loaders...

Yes I really really really really want longer pneumatics too. And much more efficient motor pump would also be nice.

Quote

LAs could be great great IF they produce micromotor which will connect directly to LA. Now it is still pain in the..to supply the torque to LA.

You couldn't really make a motor small, reliable and powerfull enough to do anything useful with an LA in this regard. Flexible axles are not really a practical option and yes, it is a pain in the  :oh3: to get torque to them in awkwad places (imagine trying to do the air tech claw rig or the newer back hoe with LAs) I suppose LAs are good for some things but they are just too limiting in where you can use them and besides, pneumatics are just way cooler  :wink:
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#37 Burf2000

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Posted 13 July 2009 - 09:37 AM

In a random bunch of lego i got, I now have a actuator and they do seem quite strong but again not that exciting

#38 trf199

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Posted 21 July 2009 - 08:35 PM

Has anyone tried making their own cable operated linear actuators? When I say cable I mean string, but string operated doesn't sound as good :). It's possible to create a virtual pneumatic cylinder by pulling the ram from opposite ends of the barrel of your virtual cylinder. I think it is easier to route the cable around your design and get good torque than it is with LEGO linear actuators, and unlike with pneumatics you get accurate motor control.

My other idea is to use Fischertechnik solenoid valves together with something like the Mindsensors NXT RCX motor driver, this would allow control from my NXT.

Any thoughts?

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#39 darksheep

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Posted 03 September 2009 - 12:29 PM

Just wana ask a may be stupped question but on the lego education site they sell theys pneumatic kits but the pumps and cylenders are made or a clear blue plastic .
Are they as strong and durable as the yellow one's ?

The reason i ask is cause i would like to buy pneumatics cause i have nonoe at the moment and want to buy 2 of these sets
http://www.active-ro...neumatics.shtml

What do you guys think ???

ps i live in south africa so buying any thing online is a mission !!
Thanks :)

Edited by darksheep, 04 September 2009 - 01:30 PM.


#40 Milan

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Posted 03 September 2009 - 01:32 PM

As far as I know, they are the same as the yellow cylinders!
Just trans-clear to provide better view what is going on inside.
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#41 Blakbird

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Posted 06 September 2009 - 03:31 AM

View Postdarksheep, on Sep 3 2009, 04:29 AM, said:

Just wana ask a may be stupped question but on the lego education site they sell theys pneumatic kits but the pumps and cylenders are made or a clear blue plastic .
Are they as strong and durable as the yellow one's
I have both and while it is true that they are made of a different type of plastic, I have had no structural problems with either.  LPE Power even uses some clear ones for their pneumatic engines.
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#42 DarkShadow73

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Posted 16 October 2010 - 04:06 AM

Any opinions on pneumatic cylinders vs Linear Actuators?  I loved the 8455 Backhoe Loader and its ooziness of pneumatics, there had to be 10 feet of tubing alone in that model, it is my all-time favorite and as long as you oil the cylinders, they stay nice and I've had 2 of them since 2005.  Wish it had had an airtank like the 8464/8439/8459 Front End Loader, but there was really no realistic way to incorporate it into the superstructure and still make it look real-life, and kudos to the designer of the 8455.  I thought after the release of the 8049 Pneumatic Log Loader that Lego was going back to pneumatics and thought we would see more models with them this summer.  Odd how they came out with them just in that model, and it was nice being able to add PF elements to create a compressor for the pneumatic log arm.

#43 Sinner

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Posted 16 October 2010 - 04:54 AM

View PostTechnicFreak, on 16 October 2010 - 04:06 AM, said:

Any opinions on pneumatic cylinders vs Linear Actuators?
Yes! A whole topic.  :sweet:





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#44 allanp

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Posted 16 October 2010 - 10:49 AM

Pneumatics are faster, stronger, more reliable, far more realistic, are cooler, more authentic, more useable and just about better in every way than LAs.

The only advantages LAs have is their absolute pricise positioning (pneumatics can be positioned more than pricisely enough for most cases anyway!) and they are a bit longer (pneumatics really should be made to be about twice as long as they are now to be in scale with todays larger sets). I like that some sets have nice complicated gear trains to drive them, but you don't have to have LAs in order to have nice complicated drive trains. Besides the drive trains in the 8043 to the actuators really aren't that exciting, just a couple of gears and a bunch of UJs. The majority of the complexity of that set was in driving the tracks. When you consider how much the LA does for you (converts a fast rotary motion into a slow linear motion in one single part), it's too much to be done for you. Technic is a toy but it is more than that. It is unique in how it recreates real life mechanics and machines in a authentic way. It's not like having a toy, it's like having the real thing under the christmas tree. As a child, there was nothing cooler than that. When have you ever seen a front end loader in real life powered by LAs? I know they are not powered pneumatically either but it is a fluid under pressure moving a ram. That's just so much more real than LAs which just seem far too detatched from the real thing to give that same sence of having the real thing, just smaller.

To sum up, Pneumatics encapsulate everything that is good about technic. They work great and just like the real thing and are fun to play with. LAs on the other hand are tedious, boring and brings technic down into the realms of just another toy.
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#45 Sinner

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Posted 16 October 2010 - 11:02 AM

View Postallanp, on 16 October 2010 - 10:49 AM, said:

To sum up, Pneumatics encapsulate everything that is good about technic. They work great and just like the real thing and are fun to play with. LAs on the other hand are tedious, boring and brings technic down into the realms of just another toy.
:tongue: I do mostly agree with you, but you forgot one of the LA advantages; they stay where they are put. I (when it was assembled) liked leaving 8421 with the boom up, and that required that I re-pump it regularly. Same story when the crane was lifting. Not a big deal I know, but it is one of the things I like about LAs.





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#46 allanp

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Posted 16 October 2010 - 04:53 PM

View PostSiegfried, on 16 October 2010 - 11:02 AM, said:

:tongue: I do mostly agree with you, but you forgot one of the LA advantages; they stay where they are put. I (when it was assembled) liked leaving 8421 with the boom up, and that required that I re-pump it regularly. Same story when the crane was lifting. Not a big deal I know, but it is one of the things I like about LAs.

Well if ou call THAT an advantage.... :tongue:
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#47 Pauger

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Posted 16 October 2010 - 09:15 PM

View Postallanp, on 16 October 2010 - 04:53 PM, said:

Well if ou call THAT an advantage.... :tongue:

It is. A big one aswell.

Edited by Pauger, 16 October 2010 - 09:15 PM.


#48 Paul B

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Posted 19 October 2010 - 01:50 AM

Being from the "old school" back when we only had the pneumatics I have a soft spot for them but in recent times I can see the benefits of LA's and think both have a place in modern Lego Technic sets. Over the weekend I built sets with both and found they are both enjoyable to build and use.

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#49 Aris

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Posted 30 July 2012 - 12:08 AM

View Postallanp, on 16 October 2010 - 10:49 AM, said:

Pneumatics are faster, stronger, more reliable, far more realistic, are cooler, more authentic, more useable and just about better in every way than LAs.

The only advantages LAs have is their absolute pricise positioning (pneumatics can be positioned more than pricisely enough for most cases anyway!) and they are a bit longer (pneumatics really should be made to be about twice as long as they are now to be in scale with todays larger sets). I like that some sets have nice complicated gear trains to drive them, but you don't have to have LAs in order to have nice complicated drive trains. Besides the drive trains in the 8043 to the actuators really aren't that exciting, just a couple of gears and a bunch of UJs. The majority of the complexity of that set was in driving the tracks. When you consider how much the LA does for you (converts a fast rotary motion into a slow linear motion in one single part), it's too much to be done for you. Technic is a toy but it is more than that. It is unique in how it recreates real life mechanics and machines in a authentic way. It's not like having a toy, it's like having the real thing under the christmas tree. As a child, there was nothing cooler than that. When have you ever seen a front end loader in real life powered by LAs? I know they are not powered pneumatically either but it is a fluid under pressure moving a ram. That's just so much more real than LAs which just seem far too detatched from the real thing to give that same sence of having the real thing, just smaller.

To sum up, Pneumatics encapsulate everything that is good about technic. They work great and just like the real thing and are fun to play with. LAs on the other hand are tedious, boring and brings technic down into the realms of just another toy.

I totally agree.I love pneumatics. Another great advantage is the fact that you are able to place them even on long distances(even whole meters away from the air compressor) without having any chance of losing of their power.Imagine doing this by using linear actuators.Imagine the friction. :hmpf_bad: Huge disappointment as for the power. Also the air transmission of pneumatic cylinders is quicker that's why they correspond much faster than LAs.

I totally agree.I love pneumatics. Another great advantage is the fact that you are able to place them even on long distances(even whole meters away from the air compressor) without having any chance of losing their power.Imagine doing this by using linear actuators.Imagine the friction. :hmpf_bad: Huge disappointment as for the power. Also the air transmission of pneumatic cylinders is quicker that's why they correspond much faster than LAs.
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#50 SheepEater

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Posted 30 July 2012 - 12:13 AM

Pneumatics all the way.

I hate LAs. I much prefer clever construction with WORM GEARS and GEAR RACKS, which while taking more space, achieve the same thing.

Edited by SheepEater, 30 July 2012 - 12:13 AM.




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