RaguTom's Build - 6DOF on a budget!

Very nice work @RaguTom! coding and welding are interesting skills

These metal gears motors look tough!
Could you please give us a link and some specification : torque and speed?
thks

i would suggest flipping the levers 180 degrees to the outside. this will give you more stability, leverage and will lower the platform some. although ill bet you have to still trim the rods by at least 1/3. looks good so far tho. i like the custom aluminum work, very fancy.

EDIT: I see that flipping the levers would change the orientation of the upper platform. I do believe this is necessary. the connections for the motors should be parallel. this would reorient the top about 120degrees in either direction.

also those heim joints will wear fast introducing slop. i suggest tie rod ends from the auto industry. I started with heim joints and quickly wore them out.

Thanks @bruce stephen! We chopped the rods down quite a bit and also made the upper platform a little smaller (we still have the original just in case). I was going to go with tie rod ends until I found these heim joints from QS Components. We might end up with tie rod ends anyway. Should be pretty easy to switch over.

@RacingMat http://www.monsterscooterparts.com/...su/motor-gearbox-invacare-pronto-m5a-m61.html
I'm only providing THIS link because it will be more permanent than an EBAY link. I DO NOT suggest spending $500+ on each motor! You can find them on ebay wayyyyy cheaper, and a used one is just as good as a new one. Better yet, steal grandma's wheel chair and rip them off of it

@RacingMat Also, for the time being, don't run out and grab a bunch yet. We have tested individual motors for capacity, but haven't put their combined force onto a rig yet. Who knows, they may suck! Or they may burn up from the current we are trying to draw through them.

I have 12mm heim joints and they have been working great for over 18 month No slop and nice and sturdy

UPDATE: We powered everything up Friday and got motion!!! We identified a few problems with the board layout and also got to experience what happens to a platform when you don't set the right limits! Damn thing could have launched something through the ceiling! Luckily, nothing binded up and even though it isn't supposed to, the arms ARE able to do almost 180 degrees of motion

The board layout is now version 2.0 and we are sending it for printing Monday or Tuesday. It is completely redesigned. It will have the same features, just 6 separate boards printed as 1 snap apart board. The cabling looked like a nightmare with it all on one board. This way you can keep the drivers next to the motors and power supplies at each of the 6 points. The 6 boards communicate through a 2 wire link to each other. The board and parts cost stays about the same. It is also getting much beefier FETS. The current handling capabilities will be much improved!

Stay tuned for more updates! Platform building is all a learning experience to us and we are taking our time to do it right and to learn from our mistakes.

Tom

Latest update: Its getting there. We are finally sending the new board design to be printed, this week. I am also working on the top frame. Finally have all six power supplies as well!

Tom

UPDATE: It has been a while since I have posted here. Since my last post, my wife and I have welcomed a new daughter to our family. She is healthy and happy!

You can tell why there haven't been many updates, but the progress has been tremendous. We have taken advice from the group here and shortened the arms and flipped the motors. It is incredible how stable this thing is now. We have fully tested the new controller design and it is amazing to say the least. We opted for individual cut-apart controllers printed on a single board. This allows us to keep the power supply leads and motor leads very short. We used 100 amp FETS on the H-bridge and it still contains the majority of features that the previous board design had. WiFi communication on this thing is near flawless.

We made the levers 6 inches instead of 8, as we were blown away by the amount of motion that 8 inches brings. I think many of us started with this thought: lets make the levers as big as humanly possible to get crazy motion. Well.....DON'T. Not only is it not necessary, but it is downright uncomfortable. Also, don't fall in the trap of saying: we can make the levers huge, but we can tame it down in software... that's just a waste of precious power.

With the current setup, we are able to lift well over 300 lbs and the power supplies, motors, and controllers don't care. We have not found the upper limit to how much we can lift, and probably won't any time soon. we allowed for a 100 pound cockpit, but using aluminum box tubing, I have that number down to 20 pounds on just the metal. Add another 20 pounds for the TV, 13 pounds for the seat, and around 15 or so for wheel, pedals, shifter ETC. That's 68 pounds with plenty left over for a human!

I'm excited about the results thus far, and won't be too much longer until I have a great write-up, with pictures, videos, dimensions, schematics, and everything.

Tom

Congrats to you and your wife on your baby daughter

Hi Tom,

Just wanted to ask how things were going with your build? Not sure if i have missed a thread someone where else on the forum but been keen to follow your build with your own board you have created.

Hey everyone! I hope you haven't forgot about me, because I haven't forgot about you!! In my last post I mentioned my new daughter.... she is now 17 months. I can't believe how long it has been since I have been here. We had major pressing projects at work to start and finish, most of which are done now. Once we put those to rest, we are continuing along with the rig. The poor thing has just been sitting there collecting dust with no one working on it. One of the major changes decided is the inclusion of VR. I was deeply against doing VR on this rig, because I have so many switches, buttons, and displays for the cockpit/dashboard. I'm excited about the future of Windows Mixed Reality, and I believe that will allow me to accomplish both VR and visible cockpit.

For the mechanics and electronics of the rig itself, we have a solid electronic design, as these controllers will do what we ask them to do. The motors on the other hand..... using a non matched bunch and one that was already mostly cooked, ended up causing us problems. We still want to investigate using a new motor to replace the bad one, but we are really looking forward to DIY linears. I still don't feel that the electronics are ready for public consumption, based on the configuration methods (it's not as user friendly as it should be), but they are definitely strong and mostly reliable!!!

Stay tuned! I promise it won't be 17 months before I post again!!!

Talk to you soon,
Tom

Hi Tom, this is my first read on this thread, and after reading this, I can't wait for the outcome!!!

I would put it up there with a John LeCarre novel! It as everything the audience wants; excitement, suspense, celebration, tension, and an overbearing tell of mystery.

Anyways, sounds like a great package, and I hope it comes with a "operational manual"

So sign me up!!!! if you can get to work with AC servos!

Regards Jerry.

video and photos please

Any updates ?

Remember how I said I wouldn't wait a year before I posted again.....It happened. A very busy home and work life left this project collecting dust, BUT I AM BACK ON IT AGAIN.

After using VR for months, with no sim rig, I am convinced that there is no other way to do simulation besides in VR. I did a complete 180 from being heavily against using VR with this rig... VR still has room for improvement, but the immersion far outweighs the sacrifice of some visual quality. To be honest, the only game where I am forced to really sacrifice visuals is X-Plane 11. The current state of VR in X-Plane is great, but needs HEAVY performance improvement. iRacing looks awesome, P Cars 2 looks awesome, Derail Valley looks awesome....

So...The rig.... After brushing the dust off of it, I CNCed some new feedback potentiometer mounts. This was needed to position the pots for using timing belts rather than O-rings for connection to the motor shaft. Smooth O-rings allowed the pots to slip and throw off the feedback. You would end up with a wonky sitting rig at home position.

The motors have been a sore subject for a while. I have 2 motors that were heavily abused before I obtained them. They showed signs of over heating and brush burning after short runs. I have decided that I would swap out the unmatched sets of hand me down wheelchair motors for 6 new, matched gear motors. The price of powerful gearmotors (from china and such) has REALLY come down since starting this project. We are still deciding which motors to get, but the clear winners right now look like some 24 volt 400 watt motors geared down to 60 RPM (plenty responsive for what we are doing). They produce about 40 ft lbs a piece, and coupled with some strut dampers to nullify the weight of the top platform and driver.... they should fly! The best part...about $100 a piece! Talk about 6DOF on a budget!
The only draw back with these motors is that they use a completely different coupling method than what the rig already uses. The original motors had keyed shafts, these have keyed holes to insert shafts. With any luck, the shaft sizes will be the same and I can just cut the shafts off of the old motors!! I'll get some links for you, once we test them and determine if they are suitable!

More coming soon! I'll have plans and more info as I produce it!

Tom

Can we see a video ?

I'll get a video together once the new motors are installed

Any updates? @RaguTom