Universal joint questions

http://www.ebay.ca/itm/GEAR-MOTOR-1...483?pt=LH_DefaultDomain_0&hash=item51bed470a3

Is this classified as a AC or DC motor?

DC. I believe that's why they stated permanent magnet but AC can sometimes use permanent magnets too.

It's best to have the UV joints pivot point as close as possible to the center of gravity vertically, correct?

What do you guys think of the location of the pivot point in this drawing (for the frame). Does it make sense to raise it like this?

DC my friend.

Ok the frame your looking at will have more roll than pitch actually a massive difference. Bottom uni will be close but a test can be done to find its final position. The Seat uni in the wrong place, will load the motors with all the weight of the seat plus the driver.

The pitch and roll difference can be compensated for with the software though, right?

yes, my foot motor frame had big roll, so i fixed the profile to make it even

Yes you are correct the beauty of SimTools is that we can decide on how much % of the Axis movement will be used by each force.
What makes SimTools so create , flexibility , motion software built by DIY sim guys for simmers.

I just demo'd the VRX Dbox simulator and I was not impressed at all. Hardly any movement (1 1/2" total ). Nothing like I have seen on the DIY sim videos.

Agreed.
Its not a VRX, but heres a 3DOF I played on (not me in video) at the Easter Show In Sydney a while ago. I had a run on the rally mod and even with the sheer vibration, it just didnt feel right.
And yes I have also played on a VRX as well at a place in Sydney Centre another time, same again, didnt feel right.

Dbox actuators only move about 50mm. There are 75mm and 120mm version available as well, but really, at nearly $3000 a corner, a $300 DC motor and JRK can do better.
For the really fine tactile vibration, just add bass shakers.

How much throw do you think I can get out of the motor I listed above? I would like to have a lot of movement on the frame (pitching). Like 6" up and 6" down. Is that possible with this kind of motor or should I go with something bigger?

its possible but it will depend on how heavy the frame you have in mind. From what you are suggesting, it MAY work adding more actual travel of throw, but there is no guarantee the motors will have the power to pull you back. Especially with screens on it, it will probably not work.
I built a sim a while ago for a mate , full frame, shoulder mount, screen on desk, He wanted 75mm , 3" throw up and down. It struggles sometimes and thats with 60:1 gearboxes on the motors.
I suspect you are looking at a problem.
so for more throw, you can try it, but if the motors struggle, either shorten the travel distance or go for larger motors and larger h-bridge. Or even 24v motors.
I think you were going to use an ard? is that right?

ard? I don't know what you mean. BTW I will not have the screens on the sim. They hang from my ceiling

the control board, is it arduino and h-bridge you are using?

You recommended JRK's in another thread, so I thought I would use them. Do you need an H-bridge with them?

Hi @ jimmcquade you only need the jrk.

Now I have to find a bigger motor. Anyone from Canada or Washington state USA know of a local supplier that I can get a more powerful motor from I was looking at this one bit I need something bigger.

http://www.ebay.ca/itm/GEAR-MOTOR-1...483?pt=LH_DefaultDomain_0&hash=item51bed470a3


I'm in BC, and I occasionally make trips to Washington state, so I could pick it up there if the shipping charges are too much.
Thanks

sorry, no, JRK are all in one. I missed what choice of control board you were using, if its JRKS, stick with them.

Ok @jimmcquade , again with 6" throw up and down, thats 12", a 12v 50:1 gearbox motor like what is listed is a possible no go. Thats 300mm and you would need at least 160mm long levers to allow enough swing. Because you wouldnt use the full 180 deg angle, more like 120 deg angle of the motor swing. At that length, the motors may not lift it. You could try 100:1 boxes, but again, no guarantee.
Seriously, thats a hell of a lot of swing and you will find it odd trying to look at a screen at that angle. Considering you swing back up to 6" on a hill for pitch. At your head it may be more like 10" throw.
Its a mind trick and not a "try to recreate forces like a commercial force dynamics 401 sim". They have massive throw because it makes it look good. The amount of times people have seen videos like this

including my mate and said " thats realistic, I want that with 12v" , it cannot be done with 12v motors unless you look at custom actuators.
That amount of swing is a wild ride and attracts attention, but sorry, its not producing the real deal.
This 401 has a better profile

and again, its a $70k machine.
With custom, actuators, best look at these

http://bffsimulation.com/linear-act.php
plans bought from above site.
2 of those on your frame would easily give you the 300mm travel you are considering and should cost you about $400 each ish to build.
Thats what you are looking at.

How much throw do you think I could safely get from the 50:1 motor shown above?