My diy 3DOF motion rig project

James, you can mount the roller blade wheels at right angles just make the mounts themselves the same arc as the radiaus of your rig (from the pivot point to the wheels). I did this and it works excellent.

See this part of my thread:

http://www.xsimulator.net/community...ion-rig-24v-big-motors.4603/page-9#post-52287

Hey James
I'm not using swivel castors but rigid ones which are mounted perpendicular to an imaginary line from RTL pivot at the front to centre castor. I got everything in ACAD so it's pretty easy working out the exact angle.
I actually changed my design in the meantime twice. I ordered a more solid thrust bearing and 4 ball transfer units in Germany and adjusted my design according to that.
Here some pics:


Although these ball transfers seem to be of pretty good quality I decided not to use them because they are just too noisy.
So I changed back to castors, but different low-profile ones which are approx. 40mm lower than the ones I wanted to use initially.
Here the latest design:






I changed the design of the seat frame a bit as well to be able to do some final tweaking of the seat position and angle to get it perfectly balanced.
The castors for the bottom frame I'm using now are these leveling castors from Footmaster (GDR-60F):


The pedal mounting bracket is implemented as well. I'm using seat rails to allow for adjustability as the seat is fixed in its position.
Well, haven't started building yet, but I'll order steel and get myself a gas bottle this week
Cheers

you look like you have put alot of engineering time into your project. Have you figured out your lateral forces? To me looking at your pictures it looks like you are going to mount the sway actuator at 90 degrees to the frames. with your 5 point (4 wheels , 1 barring) setup i think that might cause a uncomfortable conflict. you might have a inpactive sideways effects as the actuator tries to move the entire mid frame sideways instead of just the back. If you mount the force so that it is 90 degrees to the pivot point you should reduce the effect. i think if i draw this out it might help so what i mean better then me describing it.

Did you ever consider a baring like this?
its grease able which will prevent noise.
and with your 4 wheel design you will not have to worry about any twisting forces. Also it should be able to handle all the weight from the frames, monitors, controls, push pull forces and rider.

Yeah, there are lots of hours of design work in there. I must admit I don't see a conflict - I'd really need a sketch to understand where you see potential issues. All 4 castors are mounted in a direction exactly perpendicular to a radial line centered at the pivot/thrust bearing. Friction should be minimal so I'd expect to move the top frame with ease. The RTL actuator is mounted perpendicular to the centre axis of the rig so the lateral movement of the top frame is in line with the actuator.
I like these bearings. They seem to be very solid. Hard to say not knowing dimensions. It looks like they are very suitable for RTL - probably better quality than the bearing I got.
Mine has a max. load of 600kg. On top of that I got 2 castors either side with 200kg each which makes 1000kg for just the front part of the rig.
Can you give me some more info on that bearing?
Cheers

Hi Thirsty,

Nice drawings!
I had a look at them: I noticed that maybe it would be difficult to enter your sim...
;-)

Might be but think he will slide in ok, not as bad as a joyrider frame is to get into, they are a pain but the flight motion is perfect in them.

Hey Mat
Access & egress is actually a major improvement to the previous design. It wasn't really good before because there was nothing to support myself when getting in/out. Although I'm sitting pretty high in there the heel plate is just 30mm below the seat and the floor plate another 80mm lower. The new handle bars either side are 250mm higher than the seat and that is just enough to heave myself out of the rig.
Works well - tested it. There was no support there before and that would have caused problems. Having the screens so close it is important to have these handle bars so you can heave and pull yourself away from the screens.
Thanks

Oh, I see what you mean! That's fine!

well i hand drew a little diagram
the lower (sub) frame is blue and your mid frame is red.
the first picture suggests the possible forces if you mount an actuator 90 degrees sub-frame to mid-frame.
the second suggest the possible forces if you mount 90 degrees to pivot the pencil added frame is optional because you can always just move the actuator closer to the back. but the closer to the seat it is the less force is felt.

the bearing are inexpencive.

http://www.princessauto.com/pal/en/Bearings/1-2-in-2-Bolt-Flange-Mount-Bearing-Assembly/3870169.p

http://www.bearingson.com/Category/...ries/1_2-bolt_flange_bearings_ucfl_205-16.asp

What are those joints called that you used onb the monitor arms?

Hi, just had a look at that awesome Opensimwheel thread here...very interesting, like it and think about getting into as well.
Changed my motion rig design again. When putting proper thought into tactile feedback I changed my mind again and went back to separated monitors.
All the tubing is smaller and that makes the rig a lot lighter. The Simx seat mover actuator mounting and dampening kit will be shortened - all angles will be exactly the same though.
The good thing is I finally started welding that thing up and that prevents me from making design changes;-)
The K-woon bass shakers and the Logitech Z906 speaker are modelled as well.

Here the new design:



...and this is what it looks like atm:



Hope a little bit it will be done by the end of the year

Cheers

ha! the direct drive 1000kW MIGE DIY wheel is the best! After using this, you cannot use a toy wheel anymore!

@Thirsty , I wondered what happened to you.
Good to see some progress.
Are you still going to use Simtools or did the people at ISRTV convince you that simcommander is better even though its not.

Hi James
Thank you very much for your post, your sketch and for explaining your concerns. Yeah, and I'm really sorry about the late response.
I must admit I struggle a bit understanding your sketch on the left, but I think the way my rear traction loss works is pretty much the way you show in sketch 2 on the right. The RTL actuator is orientated perpendicularly to the centre axis of the base & top frame. I find it a bit difficult to explain, but that's because the actuator has to operate tangentially on a circle centered at the pivot with a radius of the distance from pivot to the actuator. I'm estimating significantly more than 90% of the mass (rig & occupant) the rear traction loss actuator is moving is located (looking at it in longitudinal direction) in front of the actuator and therefore I hardly expect any lateral forces applied to the front pivot and the castors at the front.
Cheers

I wonder how these diy dd wheels compare to commercial options like the Bodnar or the upcoming Accuforce. I couldn't find any comparisons between the Bodnar and a diy wheel.
It's pretty easy to measure speed and torque, but what I'd like to know is, are there any differences in the way the game's input signals get processed and translated into FF. I'd think the controller plays a major role in how realistic the wheel feels.
You got any idea about that?
The Bodnar is not an option because of its price. The Accuforce is more affordable, but Simx's poor customer service puts me off.
Might still get the Accuforce...all depends on how diy wheels compare to it. I find it amazing how helpful the community around the Open Simwheel project is...yeah, and Simx doesn't even manage to respond to emails even though they make money with that.
Cheers

Thanks mate. Yeah, I got the whole Simx package, Sim Commander 4 is on its way and I actually thought it's the best motion software available. That's just based on what I got of the net and the way I interpret that though. I can be completely wrong there of course. Can you explain what Simtools is doing better and if there are any advantages on Simx's side.
Again, I'm everything but a Simx fanboy. They pretty much treat me as a customer without any care & respect anyway.
Cheers

That's just diy swivel joints. I was planning on putting in slotted holes arranged perpendicularly to each other. That would have given me the chance to do some adjustment and use different 24" monitors as well.
The range of adjustability was pretty small though - no chance to use screens of a different size.
Cheers

hey man. That doesnt surprise me about Bernard. He is well supported on ISRTV but thats because he pays advertising.
As you found and others have, Benards a prick first class.
Some of us were hammering the claims on ISRTV site, but we were eventually banned.
Simcommander is set up for one device so its easier to set profiles, but thats about it.
Simtools is multi device and takes a tad more but people like @nclabs can help you get converted over.
Simx ,Its a bit slower in actual plugin timing, unless Bernard has improved it, dunno. Its still based off old xsim code.
Simx software plug ins run at 40 ms I think
Simtools runs at 20ms
Simx uses algorithm to get motion, what they think the vehicle in game should do
Simtools uses raw data, what the car actually does.
Simx 41 plugins I think.
Simtools 55 plugins.
I have heard a few rumors of simx guys converting to simtools because its better.
Cheers, Dave.