Kermit Kong's 6DOF Project

sorry but the question I asked it to kermitkong......I must answer him not you

Hi @thecure

Let’s relaxing....
I will post all the drawings of my work when it’s finished. Also will post more videos about how it’s build . Actually the Plattform is in the welding process.

Mmm. You joined in 2011?, I was mistakenly just trying to point you in the right direction, as not everyone has the spare time to make how-to's for their projects. I although have no issues in complying to your wishes. Good luck in your project.

tks again.......!!!!

here the 1st test-run of the actuator with SimTools

total mess

all the actuators mounted. plattform will be mounted tonight.
looking forward to have the 1st 6DOF test-run soon.

be tuned

finally assembled


hope i can setup SimTools tomorrow

Just one question from a newbie - i can see that you switched from motor+gearbox combo to linear actuator and well that's a theme across the builds i see in the forum ... but WHY ?

What is the benefit of using the line actuators over motor + gearboxes, especially that you already had this assembled with gearboxes ...?

hi @pchelka

well i'd like the 6DOF plattform with wormdrive gears. But i could not accept the gear backlash which is normal for gearboxes. The backslash was notable at any time when a load cycle was happen. not much but notable.

Also the non-linearity of the servo-lever (sinus-travel) was also something what i dont like it so much, of course this can be compensate for a cost of resolution in the upper and lower end of the travel.

at the end i came to the conclusion to build my own linear-actuators and modify my rig.
i expect more harmony (linearity) of the whole actuator-travel and also more stability during load cycles.
Of course this cost money (a lot of money), but lets see how nice this will be

ok i think i understood the reasons

- eventual noise of linear actuator is a drawback vs motor+gearbox,
- linear movement across all the range is a benefit.
- same resolution in any pointof travel is a benefit for linear accuator

Another question - you noticed backlash, ok got that but the movement resolution difference - is that actually noticeable ?

Hi,

Yes it is notable if the Servo lever reach the lower and upper limit (6 o’clock and 12 o’clock).
That’s why an optimal usecase of the lever is beteeen 8 and 10 o’clock . A typical range from 7 to 11 o’clock is often used.

This small optimal range decrease the practical travel of the lever which can be use.
This can be compensate a little bit with a longer lever, but this will also dramatically increase the backslash issue.

I mean the worm gear drive is good. I will not say this is bad, you know.
A lot of good rigs use worm gears and Servo levers. But the top of the edge is the linear actuator, if the actuator is fast enough, and strong enough.

Best,
Kermit

Thank you this is very valuable information.

I'm potentially looking at a 6dof build so this helps me to decide and plan ahead,
now its a matter if one can get a linear actuator to be 'quiet' during operations... with a limited space and family members sleeping near by this is kind of important

to have a silent linear actuators, i think is difficult because of the nature of ball-scew inside the actuators.

a silent worm drive system is much easier to realize. E.g. my motors and worm gears which i have left from my modified rig are totally silent because of the size/power of motors and worm gears. The worm gears are size-50 and the motors have 24V/490 Watt.

my new linear actuator compared to the worm gear drive, are really noisy. This is the bad side of the coin

Hi kermitkong dit you grease youre ballscrews ?

Hi adgun,

Yes, I greased the Ball screws and also the gliding-shafts....

Did you greased the nuth and fit a grease nipple ore just the screw

The grease nipple and the nut was already full of grease, so I greased only the screw...

Hows about a video whilst you are playing ED ? lets see how it moves

Hi Craig,
I will do it, when I’m done to fix the noise issue with one of the actuators.
I hope I can upload a 1st quick video tonight.
Will be only a video made with an iPhone, because I don’t have the fancy setup with a GoPro or so. Also don’t know how to mix the game video with external video sources , never done it before.

but the noise for me is normal.....the sound of friction is normal..... is't possible to soundproof whit cover the actuator..