Question 6DOF Motion Simulator on Yalu Wheelchair motors - need advice...

After immensely enjoying my DIY 2DOF VR Motion Simulator for 3 years, I'm planning to build a compact and ultra-low budget 6DOF platform. I'm inspired by Keith's project - it looks like his rig was working fine with inexpensive Yalu wheelchair motors. Here's what I'm thinking after some research - please advise if anything doesn't make sense or better solutions can be found.

First, here are my requirements and constrains:

1. It has to be ultra-low budget. It's still expensive even with cheaper motors and I have to keep cost under control.
2. I have limited room, so it has to be compact. I'm looking at keeping motor arms oriented inwards, Like the FlyPT model suggests, and keeping the base smaller than Keith's platform. The footprint would be roughly 110 x 150cm, which is about the maximum I can fit here.
3. I have no welding equipment and experience and no heavy tools, so I'm limited by hand-held power tools + a circular saw. Therefore I'm planning to build everything from wood and plywood, except of course for motor arms, rods, motor and rod connection points etc.
4. Looks like the local cheaper rods from Home Depot all have the wrong thread (1/2-13) that I can't find rod ends for, so I'm limited to what I can order from Ali Express etc. The longest rods I found there are 500mm, so that's my limit. According to FlyPT Mover, they should work fine.
5. I'm using a motion simulator almost exclusively for civilian flight simulation (MSFS), with occasional driving. I'm not a racer, so the speed and powerful rapid micro-movements are not important. As long as it can do nice smooth and long movements and reproduce medium-size bumps reasonably well, I'm good.

After analyzing Keith's photos and adjusting for my requirements, here are the parameters in FlyPT Mover. They seem efficient, but all advice is welcome. Rods are at 90 degrees angle to 60mm motor arms. Rods are on a fully vertical plane perpendicular to ground, looking from above. The side angle is close to 45 degrees, maybe a bit larger.




The individual maximum ranges according to FlyPT:

Roll -+11deg
Pitch +-11deg
Sway +-100mm
Surge +-112mm
Heave +-68mm
Yaw +-16deg

MOTORS - YALU MY1016ZL-75 : 6 x ~$50 = $300 + shipping

Based on Sebastian's thread, the calculations for those motors would be like this:


YALU MY1016ZL-75 calculations: Static Load = Torque_per_Motor * Number_of_Motors / CTC = 36Nm*6/0100= 2160 N or 220kg not bad

It's a VR rig, so no monitors, the seat would be a light gaming chair (not a real racing chair). I weigh 82kg, and it would be nice to support up to 100kg pilot but no more is needed. Even with wooden frame, it shouldn't weigh more than about 50kg with all peripherals. So 150kg max. I don't know how to calculate a dynamic load, but it seems OK to me. I doubt that this rig could deliver more than 1.5G loads.

- Would these motors be enough to power a 6DOF platform? That's literally a $1000 question

- Would there be any harmful reverse current from these motors? Keith's rig seems to have no problems from it and I don't see any protection (i.e. battery or voltage regulators etc.). I don't have any such problems with PGSaw motors. Should I be worried about that?



POWER SUPPLY

Looks like he's running dual 12V server PSUs. I have 2 of popular HP 750W PSUs and maybe I could get more for free. I guess I would need 4 of them - 2 pairs in serial powering 3 250W motors per pair. He somehow got away with only one pair, but maybe his PSUs are more powerful.

- Will serial 12V PSUs work at 24V reliably? If not I can buy WINWELL 24V PSUs but I'd rather use free ones if I can.

ELECTRONICS : ~$160

3 x Arduino boards running SMC3 which I know how to work with. Each board controls 2 motors.
3 x 100A Motor Driver - I would love to work with cheap IBT-2 drivers, but I read that they are not reliable at 24V, so I'd have to get the pricy 100A drivers, controlling 2 motors each.


RODS : $85
M12 x 500mm fully threaded rods. Dual-threaded may look nicer if I can find them. It would be nice to find cheaper options. If I find someone to weld things for me around Toronto area, maybe I'll by cheap threaded rods at Home Depot with the wrong thread, and just weld the ends.

ROD ENDS : $43

M12 ball joint ends @$2.50 each + shipping.



ANGLE SENSORS

I will use either a short belt drive + hall potentiometers that Keith was using, or 2 gears without belt that some people are using, but most likely I will repeat the same arrangement I use on my 2DOF. I 3dprinted magnet holders for the shaft end, mounted a bunch of round magnets sideways and 3D-printed a hall sensor holder for dirt-cheap hall sensors (~$3 for 10 sensors). As magnets rotate, sensor acts as the pot. It only provides 180 degrees and then goes backwards, but as motors would only be using a maximum 90 degrees, it's fine and has a decent safety margin. It works really well in my 2DOF with PGWaw motors - see photo. The challenge would be having enough room so the rods won't collide with the sensors, because with Yalu motors the shaft is only accessible on one end, but I think there should be enough room there.

Advice is welcome!

Here is my current calculations for the build. I appreciate all the advice. I'm especially concerned with the motors. I'm also including the FlyPT Config file.

Combining two 12V power supplies into one 24V power supply requires tampering with one of the power supplies more info in this thread https://www.xsimulator.net/community/threads/wiring-server-psus-in-parallel.6251/
I point out that I don't know anything about electrics , but it looks like a potentially dangerous procedure.
Well, and the noise of server power supplies is high.
In my 2DOF I use GYUSPW S-600-24 25A power supplies connected in parallel to bridge 100A. Which admittedly you have to buy 6 but they are cheap.

As for reverse current, I successfully use the KBPC 5010W diode solution as shown in these threadshttps://www.xsimulator.net/community/threads/power-supply-tripping.13110/
https://www.xsimulator.net/community/threads/keiths-2dof-rig.14363/page-4#post-230224

Thanks a lot, that's a very important info I didn't know about! I found a good video with the mod, and it looks easy, I can do that. So that's an option if I can get those PSU for free.


The diode is cheap on Ali and is a great idea.

I think I will also be adding 3 gas struts to unload most of the weight of the rig from the motors. Considering the borderline motor power it should help a lot at a very little cost. It may also smooth the motion a little bit. These struts have more or less the right range of motion and weight rating, as far as I can tell. At 54,4kg each, they should support ~162 kg of the rig+pilot when fully extended. I'm not sure if I should be aiming to compensate the whole weight, or half, or some other amount. I've never worked with struts before...

I am thinking about doing something similar. How the project going so far?

So far so good, but it's still not complete. You can follow the progress here: https://www.xsimulator.net/communit...transducers-controls.19053/page-4#post-252685