6DOF motion platform using ODrive

Hi all!
After some days of confusion and frustration I calmed down a little and continued my project. Thats also because I made a small redesign around to motor area in order to be able to have have the possibility to use other motors that I might have to use for a relapse solution. That removes a little the fear from a complete failure. Now I could use motors up to 100mm length :slight_smile:

So I started to think about some noise improvements.
I tried to wrap my yoga mat around the actuator to see the impact in noise reduction . And because it is a verry heavy mat (thats important!) made from natural rubber (also important :wink:) , it seems to be perfect for damping noise. So I deceded to sew a jacket and ordered the same Joga mat in a prefered colour that fits in my living room :grimacing:…only for a while :rofl:.
And what can I say - It was such a fun to sew the jacket together with my son, although we had no experience with sewing…
Although the actuator never was loud, now it purres like a cat :cat: …and looks so cool with its new jacket.
Here you can see the result and our short sound check with highspeed ( the loundspeaker of the TV was fairly low at this test!)


(note: this is not the final cable cover, but showes how it will look like later)

@Jake_Ketchum
nice to have you here at the party! You are allways wellcome!

kind regards
Wickie

3 Likes

Hi

Have you already been able to use FlyPT or do you still use SimTools?

If so, what are the commands you are sending with FlyPT, do they look like this:
[p 0 ]
Or like this:
p 0 <13>

Cheers

Carelsbergh Stijn

Hi Stijn
sorry, I still “work” with Simtools. As I wrote some posts bevore, my work with Odrive is a little on hold and I concentrate more on optimizing the mechanical design. After this I will continue with some measurements about the power consumption. Today I ordered a 36V, 350W power supply from Meanwell for first Tests with my actuator.

I hope so much, that you can manage to solve the problems you still have. I follow all your comments, but cant really help - sorry!
Good luck!!!

kind regards
Wickie

Hi all,
the last two weeks have been very productive with help of my son. I got the lasercut- and bent parts for the universal joints. They look really great and are very precise. So I could finish two komplete joints and add them to my actuator prototype.
The joints are extreme robust and dont have any recognizable backlash.

So for the low material cost of aproximately 25,- each , the design of the jonts could be a also a great solution for other DIY sim builders.


(ups, forgot one washer…)

Yesterday I build up a simple test stand. It ist made from cheap wood and although its creaking like a old castle door it works good.

Finally I put the new 36V, 350W power source from meanwell to the system.

To simulate the load of the platform and driver I put aprox 30 kg weight onto the build.

What we have seen at the first runs was mindblowing :scream::scream:!!! :

It seems that the actuator has an easy game with all the weight put on it! – And after aprox 15 minutes testing, the motor and the power source remained cold !!!
Because all test were done without the internal air spring and the tests went good, maybe the airspring seem not really be necessary for the 6DOF simulator. I will do more tests and see…

The next steps will be again to optimise the actuator design taking into account all what I have learned so far.

What still need to be solved is the motor calibration sequence that needs to be done without or only with little load. My tests showed me, that with a load of aprox 10 kg it still works, but with 15 kg it fails.
Maybe a short spring or a rubber damper in the lower internal endstop can help…

kind regards
Wickie7

3 Likes

Hi

You are back on track, well done, I’ve also posted an update on my racesimulator, take a look :wink:

What is your speed limit set on?

Keep up the good work!

Cheers

Hi Wickie,
nice to see your progress.
Greetings / Zennix

Hi Wickie, what a great job you are doing! I hope one day real soon (cruise ships are holding me back) Then I will follow your lead :star_struck:

Regards Jerry.

Hello.

I did not find positioning procedure.
Are you going to implement exact 3d positioning?

For Steward’s platform (hexapod) there is some math to resolve tajectory.
If you write something about it that I’ve missed, please point me, I’d love to read it.

Regards and good luck

Hi Bart,
currrently I only intend to make positioning with help of the SimTools simulator Software and a plugin from
FlyPt:
https://www.xsimulator.net/communit…hexapod-interface-for-linear-actuators.12859/

But with help of an apropriate Software you would also be able to make exact positionings.
I hope I understood your question correct.
regards
Wickie

Hi all
preparing for serial production…:stuck_out_tongue_winking_eye:

Wickie

2 Likes

Hi

Good luck, believe me, when you have done this once, you never want to do it again :joy:.

Cheers

Is there a link to your wonderful spreadsheet? I just uploaded Wetmelon’s firmware with endstops… is there a guide or a list of commands to using that repository?

Thanks!

:slight_smile:

Hi Tomsepe!
wellcome to the thread!
Regarding your question: My spreadsheet was a little messy, but I tried to clean it up a little bit for you.
I uploaded it to Dropbox. You can use the following link:

https://www.dropbox.com/s/0j904viqwh77yyb/Odrive-commands.ods?dl=0

Important note!!!: This sheet is only my personel understanding how commands are build in Odrive. Some of the commands was tested and worked, some was not tested, not checked and still not understood! Using those settings are at your own risk!!!

Good luck!
kind regards
Wickie

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Wickie,

Thanks!

Unfortunately though, none of the endstop commands are showing up for me.

I’m on Ubuntu and I downloaded the Wetmelon repository and tried flashing the board…
it does:
erasing… done
flashing… done
verifying…done
waiting for the device to reappear…

and then I get a bunch of errors.

But it appears as if the board got flashed… however none of the endstop commands are available.

I must be doeing something wrong…

AHH! I figured it out! I hadn’t downloaded the development tree properly! Its github’s fault. When you click on the “clone or download” button on this page: https://github.com/Wetmelon/ODrive/tree/Endstops
and if you get the link to clone “https://github.com/Wetmelon/ODrive.git” it is not the right branch.
but if you download the ZIP file it is correct from this page it is correct.
arrg so frustrating. @Wetmelon FYI

also @Wickie one important command missing from your table is homing speed:
odrv0.axis1.controller.config.homing_speed = 2000

hello together

I think it’s time for a little update on my project.
The last weeks I have continued a bit with the production of the parts. The production of several identical parts is much easier than it was with the prototype. Meanwhile more than half of the parts are finished -see picture.
This time I also produced the motor flanges as laser parts. They are super cheap and precise and only need a little rework. Very recommendable! I have also ordered some more parts, if somebody wants to rebuild my actuator…

Wickie

2 Likes

Great job.
Now, put it all together :+1:

Hi Wickie, Yes great job.

I went down the path to laser parts here in AU, but way tooo expensive ( for me at least ) so I print on; until I’m really happy with the outcome.

Talk with you soon.
Jerry.

dear community!
again some update of my project:
The last Weeks I made more thoughts about the upper part of the platform and the base.

As you can see I changed the design of the base – It was due to a proposal of my son - and what shall I say - we love it!

For the material of the base I decided to make it from reinforced concrete. The reason for this material is because I wanted to have a stable and heavy base and minimum of vibration noise coming from the actuators.
And last but not least - I think it will look super cool (at least in my opinion :slight_smile: ).

So we started to make a mould from wood and purchased cheap concrete for about 15,- € (for 90kg) - as it turned out it was too cheap !!! so during demoulding our base cracked. I also think we have been too unpatient and didnt wait long enough for hardening.
So we decided to build a new mold - and due to the lessons we learned so far, the second mold became much better than the first one.
Also this time the concrete we used was an expensive and special one that is usually used for making concrete furniture. The price was now 117,- (for 75kg). But believe me, it was worth all the money!

Now the base is finished and we are super happy :slight_smile:

The weight of the base including the reinforcement is now about 80kg – so possible to carry with two or three persons.

Here are the pictures…

regards

Wickie

1 Like