Showroom 6 dof - Odrive - BLDC - New design

Hi everybody,

I would like to present you my work about my 6 dof simulator.

Firstly, i would like to thank @PeterW , @SilentChill , @pmvcda for their inspiration and particularly " The Roach" !!!

I spend many and many hour to design this simulator that i prohibit any commercial exploitation.

I hope that all the community will help me to realise this long project.

I am french, but i will try to write in a right english ;-)

This the 3D of my simulator. I design it on Solidworks. It misses some screws and fixations of the three screen but it is just a detail. The weight of the upper base with all the equipment + pilot is about 160 Kg if i use stainless steel for the structure... (I use six 2450 W BLDC motors with 1605 - 600 mm ballscrew as @SilentChill ). What do you think about that ? Do the six motor will enough powerful for this weight ?

My rig can take an angle of 29 degrees . It was very important for in my design to have important movment for more sensation (With no limits 2 for example or plane simulation). And the most difficult, was to eliminate all the collision. But now it is OK . I spend several hours to understand and to choose the optimised dimensions for my rig. In fact, there is not a specifical dimension to have. You just must to adapt dimensions of your rig to the shape of your rig and the travel that you would like to have....

The design of my linear actuator is a mix between the model of @PeterW and @SilentChill . I integrate the axial rotation into the end of the piston. Is this rotation necessary ? And what do you think about this design ?

Hey @Will974
Nice to see you starting your project! I wish you all the best for your challenge!
Regarding the actuator fusion between @SilentChill and mine: you try to avoid rotation with help of two guide rods inside the actuator and enable rotation at the upper end of the actuator - thats funny. You simply can remove both features completely as long as you will use those strong universal joint following my design . Think about it...

Which motor driver will you use? Odrive?

Wickie

Thanks you. In fact, i would like to use an hybrid solution to have a quality and durable guide of the piston by using full self-lubricating ring, so no maintenance. In your solution, you use the piston in PTFE as a guide in contact to the alumnium tube.I guess you must have used grease to lubricate the piston. I was not convinced of the durability of your solution over time.... Perhaps if i had a self-lubricating ring on the piston, it would be better ... What do you think ?

(Please you forget to answer me about the material of the rod of your piston .... Polish stainless steel ? Thickness ? ) Thanks ;-)

@PeterW
As you already know due to a last question, i use Odrive controller and BLDC Turnigy SK3 - 6364 - 190 KV . I want the best for my simulator unlike the difficulty....

!

Hi @Will974
all my plastic parts and the pistons are made from POM - I dont use Teflon. The piston glides directly on the aluminium pipe. As you assumed, I use little low friction grease to reduce friction. After some time of use, I cant see any wear on the piston or on the aluminium - so it should be a durable solution.
If you have a good (!) 3d printer, you should be able to use special filament for gliding parts. I know IGUS is selling this kind of filament. Or you buy huge glinding rings for you piston. I also thought about to use them, but didnt.
Regarding the source for the polished rod, I spent some time to find out where I bought this over one year ago. But I found it. I bought it from an Ebay seller in UK, but also found that he doesnt exist anymore on Ebay -I am sorry.
Its very difficult to get those polished 2"-stainless steel pipes and I think you need to find a new source.
The problem in general, getting spezial parts for DIY was, that most companys only sell things to busines customers and not to private people. So lot of times Ebay is the only source.

Regarding the thickness of the pipe....I cant remember but something around 1mm.
Hope this helps

Wickie

is that a good choice for the motor as i am looking for the best and cheapest motor too

Hi @PeterW ,

Of course it would be interesting to use special ring on the piston to limit friction ..... Now, i'm going to use this type of self-lubricating ring:
https://fr.aliexpress.com/item/4000910574206.html?spm=a2g0s.9042311.0.0.5af36c378flgqg
as @SilentChill in his solution. It seems to be ok for him in contact to aluminium guide.

However, in your solution, i notice that the axial rotation of the piston is resumed by the four thread rod and they work slightly in torsion....That's why, i prefer to decouple the rotation from the translation separately... But obviously your solution works good

How does you estimate the weight of your rig (Just upper base with all equipment and the pilot) ?

I am going to use stainless steel for the upper base (40x40x1,5 mm) and the software estimate the weight to 160 Kg. (Upper base+ Pilot+ 3 screens + car equipment). I think that it will be ok, considering my calcul....(345 Kg max just for one actuator) What do you think ?

Thanks for your observation . Now, i wait all material of different orders....

Hi @Will974
The weight of my upper platform race ready is aproximately 140kg - including me with 70kg.
But nothing is near any limit - so your 160 kg should be ok
Wickie


Wickie

Hi,

While waiting for the different parts of my linear actuator, i have build a test bench for the Odrive+BLDC.
You can also see the motor plate in ABS that i will use into my actuator. It is so strong
I have also make a new design of my actuator (More fit) that i will present you next time.

@+

hello! good to see progress!

when did you order your BLDC Motors? and when did they arrive? I have been waiting over two months now for mine

Hi BDZ,

Yes, it is necessary to build a test bench to optimize the the BLDC with odrive before to mount it into the linear actuator....

I ordered my brushless moto during the confinment and it takes about 2 - 3 weeks to be delivery on the website hobbyking. 2 months you said ? It is very strange but perhaps the product was not in stock when you have ordered....
Try to have information with your tracking number or you can tel the customer service....

@+

I ordered on the 24th of April from the hong kong warehouse and it had been on backorder the entire time and Hobby King basically said they couldn't give me an update so I cancelled my order from the Hong Kong warehouse a couple of days a go and ordered directly from the Australian warehouse, hopefully speeds things up.

Hi,
The different test of the motor with odrive seems to be OK for now. Power , fast and stability. Thanks @PeterW and @SilentChill . Wait now, to integrate them into the linear actuator to set up the limit end of the linear . The ABS motor plate is very strong and the four axis doesn't move .... It is positive for the future actuator.

I have buy the piston tube in stainless steel ! thickness 1 mm so it is very light and strong ! I test the different ABS part into the piston it is perfect. I wait for the other mechanical part to continue. I can't wait to continue (I have modified the diameter of the outer tube 90 --> 80 mm !!!! It was very complicated to adjust the different component but it will be oK ! My actuator will be fit but with a big piston !!!! ah ah

Hi guys,

I have receive all components... It's time to build the first linear actuator. ✌

Nice work!
How the odrive, knows the position of the ball screw? I know there is a encoder, but how it takes the first reading for initial calibration?

Hi,

Odrive knows the position of the ballscrew as you said, with the encoder. At starting odrive, there is a process of index search. Then the actuator is ready to move after somes configurations with flyptmover and odrive firmware....It is a long story....