Linear actuator using ClearPath Integrated Servo System @ 72V DC

I think 30° is a lot. In professional Level D Full Flight Sims normally 15° is all you need. @apointner and I have booked one of those for two hours and measured the angles. I think 15° was the max in acceleration. And I think I remember it was 18° during braking.

and you aim for what ?

I aim for a setup that is tuned in such a way that it might hit an end stop only about once every operating hour I know that is not a satisfactory answer Sorry.

To be honest, I didn't even know the pitch or roll limit of my planned rig. I had to check and I found it can reach a pitch of 28° before an actuator reaches it's max travel.


Be aware that there are other limits you can run into, like the max angles of the U-joints or the max motor speed or the max motor torque.

If ever someone asks about the max angles (Pitch, Roll Yaw) of a rig, the only sensible answer would be to ask back: At which translational position (X/Y/Z)?

This body represents all possible XYZ coordinates the center of the upper platform can go to:

- You can reach the true max Pitch only when the platform is in exactly one point somewhere close (but not exactly in) the middle of that body.
- You can reach the true max Roll only when the platform is in exactly one point somewhere close (but not exactly in) the middle of that body.
- You can reach the true max Yaw only when the platform is in exactly one point somewhere close (but not exactly in) the middle of that body.

...funny thing is: Those points are not identical

I find it non sensical to specify max values for Pitch/Roll/Yaw/Surge/Sway/Heave and in my software I don't have them. All I have is a little knowledge on how filters work, and an hour of time to do some tuning. All I can say is that it is highly improbable that the rig will reach an end stop, not impossible.

I'm not sure how to call this. Maybe "the heuristic approach" would best describe it . At some point I plan on implementing an autotune algorithm, but that is still a few years into the future. So, for now, manual tuning of the filters is what it comes down to.

Dirty

Hello Dirty,

After reading the design form @FlyPT and the comments form @Thanos i decided to build a rig with servo motors. I was delighted to read your article in which your design was close to my own ideas.
Do you already have your rig working?
I am also very curious if you have an update of your Actuator design.
Do you also have the 3d print files to share.
And finally, do you also have a file of the lasercut aluminum parts.

I am very curious about your reaction.

OMG, yeah, I kinda abandoned this thread as the actuator was nearing completion

I continued the build of the rig here:
https://www.xsimulator.net/community/threads/dirtys-6dof-aasd-servos.14621/

And published a little video here:


Cheers,... Dirty

Looks pro
Congratulations

Hey Dirty,

thanks for your quick reply. That looks absolutly fantastic. I also want to use the rig for flight simulation.
I will read your new threat this weekend and surely will come back with some questions.

Any time!!!

I have another thread where I talk about the software I wrote:
https://www.xsimulator.net/community/threads/writing-a-motion-cueing-software-from-scratch.13108/

But regardless of which software you want to use (Mover, SimTools, BFF, X-Sim, Nutkicker or even your own custom), there are alway two "cornerstone" questions that will guide you the way:
1. What are the accelerations on board the vehicle?
2. What does a LP or HP filter do to the signal?

If you can get a clear picture in respect to those questions, motion cueing will become one coherent logical construct (for lack of a better term). You can solve many problems by finding answers to those questions.

Cheers,... Dirty

I couldn't help myself but read your other threat right away. I also went through the current threat again. However, I cannot find your 3D print files. Do you already have these available?
I am also curious about your drawings for the lasercut aluminum.

thanks in advance
Builder

I thought I had a link somewhere to the Fusion360 CAD files. Try this, let me know if it works. There might be some broken joints in the assembly though.

Bingo! This link works, Thanks.
It realy looks very professional. Now have to figure out how to extract the different files. But that will be tommorow. First today make a familie visit to your country.

Thanks a lot.

After a lot of reading and comparing, I think about purchasing the following servos:
80ST-M02430.These have a speed; of 3000 rpm and a torque of 2.4 Nm. Would you also recommend the SFU1610 or the SFU1605 for these servos.

SFU1610 will give 500mm/s speed, but load ability up to 80kg.

SFU1605 will give 250mm/s speed and load ability up to 160kg.

Is Speed Now Important or Torque?
It seems to me that with an 80Kg load you can move a small cockpit with a 6DOF (3 monitors, flight stick, small instrument panel etc)
Is the speed important or does this not matter much in this comparison, and should I look more at the resolution. (accuracy over a short distance)

Hi Thanos how do you get to dose low forces
2.4nm at 3000rpm is 750watt
1 watt is 1 newton with a speed of 1 meter a second, so a 750w motor delivers 1500newton at 500mm second minus efficienty ballscrew 90% gives 1350newton and 500mm sec. at rated power , and 2700newton at 250mm sec.
regards Ad

The numbers I gave are based on measurements on actual actuators... in theory they can deliver more. But you have to take in consideration other parameters of the actuators, links and bits.

Also the numbers I posted are for duty cycle 100% use of the actuator. Going above these load numbers, you will reduce the leadscrew lifetime expectancy, or introduce significant wear and tear.

Only if you are using heavy duty and well built actuators you could load them further. See for example the specs of these Scorpion actuators:

Servo Scorpion actuators
(speed:250mm/s,force:200kg,stroke:150mm/5.91 inches)
Ball screws: TBI ( Made in Taiwan, China )

Finally got fusion 360 to load on my pc..
I am interested in printing out some of the plastic parts.
I think I have exported the Slider....
maybe someone could take a look.

Hi @T R Para quick update , from what i hear fusion 360 for home use will lose a lot of functions that we take for granted now , apparently the ability to export STL files will be removed for home users so a lot of the stuff we create for 3D printing will need to be done on another package,, it was a case of it was good while it lassted unless you have $1000 a year for subs :-( Nice work though ....... now save that file on non cloud based backup

And possibly export everything now...

Thanks.. I saw that notice when I was DL'ing Fusion 360. Being a new user (a couple of hours now) I had no Idea what they were talking about....
This video may be worth looking at..
https://www.desktopmakes.com/post/changes-to-fusion-360-for-personal-use-explained