3DOF w/ heave 24V DC and arduino motion platform

Hi guys!
We almost made it! thanks to all the informations we got from several forums and tools from great people from here!

Here you will find all the informations me and my friends used to build our first simulator.
We follow the design made by @momoclic and is excellent tutorial.
Project is currently working but not finished, so updates will come.



I designed the rig with freecad, and plan to release the model once cleaned

We use 24V DC 350W motors, arduino and SMC3 code from @RufusDufus,

We decided to build the structure with steel tubes assembled by welding.


The rig so far...

The steel forks

Feedback is made with full rotating knobs and a system of double gears linked by a spring, in order to avoid dead zones.

ball joints and bearings links come from Igus

I'll update photos of details and of the finished platform.
Nelson.

The 3D model:

Bravo et merci, tu n'as pas choisi la solution la moins encombrante.
Sur ton dessin tu ne respectes pas la position des bielles assurant la symétrie du mouvement.

Pour aider d'autres concepteurs, constructeurs le guide est ici
To help other designers, builder guide is here

Bravo and thank you, you did not choose the less cumbersome solution.
Su your drawing you do not respect the position of the connecting rods ensuring the symmetry of the movement.

Thanks Momoclic!

As this will be used as a test platform, we made several holes in the base in order to have 4 different positions for the motors. This 'll give us the choice between 12, 16,20 and 24° tilt for the top board at 180° motor movement.
Yes, in the drawing the connecting rods appear straight, but we calculated the holes on the top board to be aligned with the motors axis in order to have symmetrical movement if motors go in the wrong direction.

Bravo belle initiative de pouvoir tester plusieurs angles d'inclinaison. J'ai hâte de voir un compte rendu et des vidéos
Attention to ensure the symmetry of movement the axis of the upper ball must pass through the CENTRE CRANK when it is horizontal.

Congratulations great initiative to test several angles. I'm looking forward to a report and video
Attention to ensure the symmetry of movement the axis of the upper ball joint is by CENTRE CRANK when it is horizontal.

Ok I see, currently the upper ball joint is vertical to the motor axis, it shall be vertical to the half length of the cranck when set horizontally.

OK c'est le seul positionnement qui te garantisse les mêmes valeurs de déplacement (parcours et vitesse) de la bielle en fonction de l'angle de rotation depuis le point milieu (0°, plus ou moins 90°).
En fait pas facile à décrire, les mouvements et accélérations d'une bielle sont complexes et peux de gens en tiennent compte alors que c'est un élément important pour ne pas trop s'éloigner des vérins.

OK this is the only position that guarantees you the same displacement values (speed and course) of the connecting rod according to the rotation angle from the center point (0 °, plus or minus 90 degrees).
In fact not easy to describe the movements and accelerations of a connecting rod are complex and people can take it into account while this is an important element not too far jacks.

So we had the opportunity to show our rig at Futurapolis, an event in Toulouse organized by a French national magazine (Le Point).
Thanks to @RufusDufus advices, we had no burnout on the drivers. We had no load on the platform for the demo, but people came and play hard on the joystick. We used Joystick and Xplane simtools plugins, everything just ran smoothly. Thanks for @value1 for all the writen plugins!




here is a link to a video showing the platform running
https://photos.google.com/share/AF1...?key=NWpPZFRRME52WXA4YmJhWE1IN2U3WnRzNnJIT2xB


Nelson.

Is this a DIY or commercial test rig?

DIY project, made at Artilect, a fablab in Toulouse, France.
Project took 7 weeks, starting from building the team to showing the platform at the event.
At that time, I had no experience in CAD modelling or steel welding.

Picture of the platform so far:

Hello congratulations for the project, it's fantastic! I also am planning a 3DOF, but with 4 motors, I saw from one of the first photos that you used BTS7960B, wanted to know if they were the version 43A or 68A? Are you finding well with these motor driver? Thank you.

Hi Dedrado, Thanks!
We use the 43A version. After we had smoked two and a half of them, we followed @RufusDufus advice and put some thermal grease between heatsink and PCB check this post if not sure. Now they run well, we can feel the heatsink warming. but we haven't put any charge on the platform so far.
I think these boards are good as a starter. Usually people recommend sabertooth for 24V platform, but they are more costly. If we have some bad surprises we may move to those ones.

Tell me how the BTS7970 68A perform, and don't hesitate to add thermal grease between the heatsink and the PCB, the process is really easy and can save your motor driver.

Nelson.

Good start! I think you should add reinforcement: a triangle around your 3 branches star. Under load, the basement won't resist much.
Next time, think about adding a Xsimulator and Simtools sticker for your demonstration.

Salut ! tu devrais renforcer ta structure en reliant les extrémités des 3 branches en étoile par des tubes acier en formant un triangle.
Pense à ajouter des autocollants ou un panneau Xsimulator.net et Simtools lors de tes démos

Hi rancingMat and thanks!
Yes we thought about the reinforcement, we first wanted to check if the steel star base was enough to keep the motors still. @momoclic put them in his design.

To be honest, 3 days before the event we were not sure about the software we would use to make the platform alive. The choice for SimTools was a good one, as it was quite plug and play (apart from some bugs in the configuration process: we had to clear and set the mixing settings several times before having the platform moving as expected).
All the plug'ins we tried worked fine in the first launch, so yes we'll manage to put some stickers for this forum and Simtools next time we show the platform

Thank you NelsonB, unfortunately I can not find the BTS7970 68A, but definitely take your advice for the 43A

Hello.
@NelsonB please could you tell where did you buy the motor?

Thanks

Hi RedBoom!
I bought these motors from @Wanegain, who manage to select and buy them from a chinese supplier . I think if you want the same motors you 'll have to buy directly from china, as @Wanegain doesn't plan to propose this model in his on-line store. He found new motors that could be better (oil bath gearbox if I remember well). Send him a PM if you are interested. He is based in Belgium.

Can you share the specs on the motors you are using and the ones that he said would be better?

Les moteurs sont des AC 350w, 24v, 45Nm à 50rpm avec réducteur à vis sans fin et double axe de sortie 90WZYJ08.

The motors are AC 350w, 24v, 45Nm at 50rpm with worm gear and double output shaft 90WZYJ08.