My 6DOF project

After reading awesome write ups from pmvcda (Flypt) and peacemaker I have decided to take the plunge and start building a 6dof sim.
Knowing very little at the moment I am sure there is a huge learning curve ahead.
The project plan is as follows:
Build one actuator and test with electronics and software to ensure that i get an understanding of whether this will all work. Then I will build the platform while waiting on the parts for the next 5 actuators. Last, build 5 more actuators, assemble it all, then get to setup and test.

Sounds simple when i write it like that - how hard can it be....

So far have ordered

• 550mm 1605 ballscrew.
  
• Bearings to suit.
  
• Motor and driver (BLDC-8015A+57BLF03)
• Couplers
• Arduino and electronics

I will get aluminium tube for shaft and actuator structural elements in next week or so, once I can take day off to go out and pick it up from wholesaler. I am also looking for suitable power supply. I also need to print some 3d parts and once I have measured things accurately can design and print those.

Meanwhile I will continue to research on this great forum.

With luck I will remember to take pics and post build notes as I go.

Motor+driver and ball screw have arrived. Motor arrived from China in only about a week. Awesome considering most stuff seems to take more than 6 weeks at present.
But without bearings and couplers I can't design the 3d printed parts.
And even if I could design them, I cant print them - a replacement cooling fan I need for my 3d printer is on one of those slow boats
Also bought PVC pipe today for the housing. Think it will be 65 mm pipe rather than 80 at moment.
Still searching for power supplies. Will try a 1500W 24V PSU. Hopefully I can power 3 actuators and only need 2 power supplies. If not then may need to go with 3 supplies.
A very slow start, but a start nonetheless.

The next dilemma - whether to keep a log of the parts and prices...

Today i did something dumb!!!
I started tracking costs...
My aim initially is to build one actuator and test. If all good then I can build more, or else change design, motors, etc.

Here is where its at so far. Prices are totals, not per each, and are in Australian dollars.

My first project setback today.
Went to buy aluminium tube for actuator. They were out of stock. New stock was coming but has been delayed.
Ahh Covid you are thinking....

Nope!! The last few days we have had some showers. They dont have a tarp to cover the material while it is on the truck and they don't want the aluminium to get wet.
Maybe next week I can get some and start designing the printed parts.

I created my design for the adaptor to fix the aluminium tube to the ball screw.
This is first design and I have no idea yet if it will work, is right size, will be strong enough, etc etc...
I am thinking it needs more thickness but will print one first to check dimensions.

Just realised this design is missing the tabs to stop the whole assembly from spinning.
Back to drawing board for me.
The tabs will also be needed to trigger the upper and lower limit switches inside the actuator.

Hey

You can get away without the tabs, if the rod and all of its upper connections can hold the torque of the motors. The ballnut itself then functions as an axial bearing. The error introduced this way is negligible.

Post some more pictures of the design

thanks. I may consider that.
The design will have internal rails to hold the actuator together so using them to stop twisting isn't a big deal. And unfortunately I still need some sort of stops to work upper and lower limit switches so a redesign is needed regardless.

As far as more plans...
They are all in my head at the moment so nothing on paper yet. This probably isn't the best way to work but its working for now. I will post more bits as I design them though. Unfortunately I need components so i can get exact dimensions for the next parts to build - top and bottom bearing holders.

Back to drawing board...
Was attempting to design a motor mount and bearing holder last night and discovered that the FF12 bearings have a similar hole mounting pattern to the NEMA 23 motor. Unfortunately the bolts would interfere with each other such that I would need to make 2 pieces and then bolt them together to make it work. I am worried that with the mounting holes, the centre hole and then the holes to bolt two different brackets together that the assembly will not be strong enough.

Solution - new bearings.
Have just ordered kfl001 bearing and will try them out instead. The new housing and motor mount design is certainly going to be easier.

Heading back in right direction... New motor mount and bottom bearing has been designed. These now bolt together with the 4 motor mount bolts.
I may try and print them in one piece but not sue if that will improve strength or just add more complications with fill.
Either way, until some the needed parts arrive I cant get or confirm exact measurements and cant print and test parts for size and fit.

Another week patiently waiting for parts to arrive before i can actually start building stuff properly.
A couple of lesson learned so far. I ordered bearings via Ebay from England but seller only had 3. I chased around locally and found a supplier. They could supply 10 for the price of 3 that I bought from Ebay.
Lessons - shop locally first and do plenty of research into what is available locally!!
I now have 13 bearings on the way.
The price is also steadily increasing. So far $845 for parts. For smaller parts I now have enough parts for 6 actuators - assuming the first one works as intended. Nuts and bolts are also looking like they could get expensive!
Lesson - dont overlook the small stuff if you are budgeting.

Time for a mini update...
Slowly starting to collect parts.
- PCBs and level shifters have arrived.
- Have bought steel for base (80x40x2) and steel for frames (25x38x??).
- picked up 25mm aluminium for actuator shafts but havent yet cut.
- Igus bearings have arrived.
- lower shaft bearings have also arrived. problem is the shaft doesnt run true in the bearing. bearing is off centre and shaft wobbles.
- motor coupler has arrived.
- PSU has arrived.
- also have roll of PETG filament. Bought black. turns out that black is also the weakest type. Oh well....

still waiting on
- ESP boards
- ballsrew nuts
- fan for 3d printer. (ordered another today from local supplier)

To do list while waiting for important parts like ESP boards and fan to fix 3d printer.
- Solder PCB and level shifters.
- get measurements from actual parts and design final lower motor mount and fixing method.
- Redesign top of actuator to see if I can use the extra igus bearings. thinking of having two bearings per actuator which will increase length of actuator somewhat. I need to design how that will work without having loads more printed parts.

Once i get stuff made i should be able to start posting pics of progress.

Latest status update.
Physical construction has ground to halt while i try and work out printer issues.
Steel is waiting on me to have some time to cut and weld.
I managed to have one small win - the PCB and level shifters has been soldered.
ESP32 boards arrived the other day so will add and program that soon and then can connect to a motor and try to make some SW work.

How time flies. Time for a mini status / build update.
Have soldered ESP board and programmed ESP. It flashes 5 times when powered on - so seems like program has worked. Next job to wire and test properly with a motor and some software. (a simtools download cant be far away now!)

Print issues have been largely fixed. I have been able to print a motor mount and ensure it will fit with necessary clearances. So far so good and some minor adjustments to be made before finalising the design.

Steel is still sitting in a pile out the back waiting to be cut and welded. Have been a bit to busy with work and other household projects to get to that just yet.

Total price so far is a touch under AUD$1000, which includes all parts for 1x actuator, small parts for 6x actuators and the steel framework.