[MOC] 6 DOF Table (quick and dirty) Now with pneumatics!

[schraubedrin]

In contrast to all the great builds on this Forum, here's a build that's not properly designed, well engineered or sturdy in any way:

I recently realised that i've never properly thought about Gough-Stewart platforms / six-axis platforms / ... and building one out of lego seemed like a logical step.

It consists of two hexagons, six mini-LAs and two sets of universal mounting points to bring it all together.

And here's a small gif of it working:

 

I seldom get any stuff built. Most of my ideas are quite big and when i start to build them, i'm always losing myself in perfecting little details and end up being frustrated that i didn't made any visible progress.

 

So this small and fast build was fun and still gives me a satisfactory level of complexity.

[kbalage]

I really like the concept. I know it was meant to be basic, but do you have any further plans how to control it?

[schraubedrin]

I've got to admit, modelling the kinematics is tempting. But as i don't have two NXTs or EV3s, i couldn't use this to control it electronically.

As for placing motors on the currently manual turned shafts: I thought about rebuilding it with big LAs, then i shall add motors as well

[mocbuild101]

Very interesting... isn't that the same type of platform used for aircraft flight simulators?

30 minutes ago, schraubedrin said:

I've got to admit, modelling the kinematics is tempting. But as i don't have two NXTs or EV3s, i couldn't use this to control it electronically.

What about making it with pneumatics?

[schraubedrin]

9 minutes ago, mocbuild101 said:

What about making it with pneumatics?

That was my first thought, but i decided on the cleaner look without all the tubes. And i (wrongly) thought the 2 stud base of the old cylinders might be harder to integrate.

But you're right, i think such a platform would look awesome with the new 1 x 11 Pneumatic Cylinder (but i have only one of these )

Currently i'm just waiting for the next pneumatic Set to have six new 2 x 11 Cylinders, as they have a much larger travel than the old ones.

Edited June 5, 2017 by schraubedrin

[mocbuild101]

Just now, schraubedrin said:

but i decided on the cleaner look without all the tubes.

Yes, that would need a lot of tubes!

 

Just now, schraubedrin said:

Currently i'm just waiting for the next pneumatic Set to have six new 2 x 11 Cylinders, as they have a much larger travel than the old ones.

How do you know that there is going to be another pneumatic set?

[schraubedrin]

Hope

[DrJB]

Very nicely done. I think the main challenge with this (and all other ral life applications out there), is that to control specific motions (from all 6 DOFs) would require rather complex formula since the motions of the various LA's are NOT uncoupled.

Incidentally, I have developed such formulae (as others have I'm sure) and will share them if there is interest. The next issue is how to sync/link the motions of the 6 LA's? And there, as someone pointed above, would truly require some clever programming with 2x NXT/EV3 bricks, All in all, you've built a rather 'deceptive' mechanism ('positive' deceptive in the sense that it is way more complicated than it looks) that presents multiple challenges (who doesn't like these?) in all areas of physical build, math/formulae/kinematics, and lastly NXT/EV3 programming.

Oh yes, I do like such 'multi-faceted' contraptions.   

[schraubedrin]

Thanks to mocbuild101 i built a motorized version with big LAs:

And again, here's a small video from my terrible phone:

 

[mocbuild101]

1 hour ago, schraubedrin said:

Thanks to mocbuild101 i built a motorized version with big LAs:

I did say pneumatics (not LAs), but I don't mind taking the credit for it .

I think it's much better motorized, and that turning motion in the video is amazing!

[schraubedrin]

You asked for it, here it is:

A pneumatic version of the 6-DOF-table

And here the video:

This time, the lower joints were quite difficult to design, because i wanted to have the hoses in the center of the construction. I'm not satisfied with the quality of the construction, but for a quick prototype it's okay.

This exercise helped me quite a lot to do more building and less engineering.

[mocbuild101]

Just now, schraubedrin said:

You asked for it, here it is:

A pneumatic version of the 6-DOF-table

Cool! I looks like it works much more smoothly, is it more fun to play with?

[schraubedrin]

It's definitely more fun not having to worry about the endpoints of the actuators.

But i realize that the interface does impact the play value quite a bit. My switches are unfortunately quite stiff and in a dumb layout. So i currently prefer the motorized version.

But this prototype gave me a few insights on the geometry and the importance of correct joints and their placement.

I think having a lot of BEAM 1 with 2 CROSS AXLE [180 DEG] might help producing compact joints, unfortunately they're still quite rare in my collection

 

[mocbuild101]

16 minutes ago, schraubedrin said:

unfortunately they're still quite rare in my collection

Well you're doing better than me, I didn't know they even existed! 

Edited June 7, 2017 by mocbuild101

[schraubedrin]

3 minutes ago, mocbuild101 said:

I didn't know they even existed! 

They just came out this year and they're awesome for building compact joints because they have only one free degree of freedom.

[agrof]

Love this platform, one of my dream construction in Technic! You just made me to place an order on large pneumatic cylinders... I blame You. 

Spoiler

Secret hint for EU members : https://store.bricklink.com/sawan2011#/shop?o={"itemType":"P","catID":"159"} - go to Pneumatic.

 

Edited June 7, 2017 by agrof

[schraubedrin]

1 hour ago, agrof said:

I blame You. 

I'm a little bit sorry but mostly proud to be an inspiration

I just had an idea for a much better and simpler joint structure for the pneumatic cylinder that i'll try out, even thought i don't have six of them

[schraubedrin]

@mocbuild101, you've been successful. Here's Version four, one bricklink Order away from being finished:

 

The new joints are simpler, better and sturdier. Pneumatics V2 really is easier to build with.

The new interface is much more intuitive too.

Edited June 9, 2017 by schraubedrin

[mocbuild101]

35 minutes ago, schraubedrin said:

you've been successful.

35 minutes ago, schraubedrin said:

Here's Version four, one bricklink Order away from being finished:

Very good! the tubes and valves look more organized too.

[schraubedrin]

1 hour ago, mocbuild101 said:

the tubes and valves look more organized too

Yeah, i was actually quite surprised to find twelve hose connectors in my collection. Then i had to use them, to good effect as it seems

[schraubedrin]

Here's the final Version for now:

After i realized how strong the pneumatics are, i made some rudimentary reinforcements.

And now i have a new stand for my unfinished 42056:

I really wish i had the necessary filming equipment to give you a sense of scale. It's whicked to see such a big model move with such ease:

@mocbuild101 thanks for your encouraging words. The building process was fun throughout and seeing the finished model really gives me a sense of accomplishment

 

[TechnicRCRacer]

For some reason, this kind ov reminds me of Control Center II!

[Samolot]

 

I used to build such a simulator on small pneumatic cylinders

 

 

 

 

[schraubedrin]

15 hours ago, Samolot said:

I used to build such a simulator on small pneumatic cylinders

While building mine i actually thought about your model and couldn't fathom how you managed to create the necessary joints for such a small scale. Then i realized that a universal joint wasn't necessary and any joint leaving 2 degrees freedom in rotation was good enough.

Thanks a lot for the pictures, it's great to see your compact solution!