2DOF motion simulator build

Hello all!

I've been plannin on building myself a 2DOF motion simulator for a while. It's mainly meant as a flying simulator, but I'll definetly will be using it for some driving. That is, if I manage to build the thing

Here's couple of pictures of my plan:

The stick in the front is meant as a oculus rift's tracking camera mount.
I have not done any math on the required torgue etc. I just drew it and the design might change a lot. I'd like to know if there's something terribly flawed in my plan making the simulator unusable? I've also thought about placing the motors to the front to save some space, but I'll have to read some more about that.

I'm planning on building the moving frame out of aluminium, but I have a little problem with it. I plan on using aluminium extrusion profile thingys ( like this http://www.aluminum-profiles.com/products/33.jpg ), but I have no idea what the diameter of the aluminium should be so it can hold a human without bending. I found couple of local companies that sell that type of profile with 3-4 cm diameter.is 4cm diameter strong enough to hold a human?

For the motors I'm planning to use two of these (left and right handed):
http://www.ebay.co.uk/itm/12V-DC-Ge...al_Components_Supplies_ET&hash=item19f0dd7b66

and to drive them I'm planning on using two Pololu Dual VNH5019 Motor Drivers, one for each as they suck 23A per motor. I also have one arduino lying around somewhere without a proper use, so I'll be using that to control the simulator.

I haven't yet decided on the power supply, but I think I'll end up using a normal computer power supply (something along the lines of 700W) or see if I can get some server PSU from work.

I attached the sketchup file also (the zip), if someone wants to see/use it. there are some sketchyphysics components, so you probably need that plugin installed.

We'll see how this goes.

-Ville


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Edit:

The sim is now "finished". Here's a couple of photos of it:


and two videos:




I've attached file Frame.zip It contains a google sketchUp file of the frame (you can take measurements of it with the tape measure tool).

diagram looks good.

Thanks for the heads up. I'll have to experiment with it when I get the thing build. the vibration sounds like it's going to cause a lot of "rift" sickness.

I just ordered the motors, hopefully they arrive soon!

I've been thinking about the motor placement. I want the simulator to be as small as possible (so that the person that I live with, lets me put it in our apartment). So I'm thinking about placing the motors underneath the motion platform instead of a shoulder mount.
Is there any difference if I place the motors to the front or the back of the sim?


Next on my list is to contact someone who sells aluminium profile and see how much they're going to cost.

[edit] I did some reading and it seems like the best place is to place the motors to the front and attach the moving arms at least to the height of the seat.

If you want screen on and compact, its a problem.
You will have to make the motor mounts higher like this, even with 60:1 boxes on them to over come the extra weight, like a TV that is high up on the frame.

Thanks for the info. This will not be a problem as I'm going to use Oculus Rift with the sim.

mount them higher anyway

You can lower your seat too. Remember the length of your motor arms will be the distance of travel.

mount them higher anyway

Im not talking about the motor and rod mounts, Im talking about the main drive shaft pivot. Unless you want to be high up in the air for a reason. If you start to add anything that goes from fram to seat carriage it will have to be longer just becuase your pivot is higher.

good point, sorry I overlooked that

I've done some more designing on the frame:

The seat will be at the left side of the frame, Pivot point will be at the wider cross beam at the back. The motor rod mounts will be somewhere on the beams with the red dot.
How far the motor rod mounts on the frame should be from the pivot point?

I also lowered the seat by 4cm in the new design. I think that's the lowest that I can get it with a simple design.

you said
"How far the motor rod mounts on the frame should be from the pivot point?"
There is no real set distance, but as it is a full frame, Id suggest as far as possible from pivot.
Now with you mounting the motor connections high up, as long as you are not too heavy, like under 100kg, somewhere about knee distance or even towards the feet would be ideal.

3030 aluminium profile is strong enough to build the frame。

My motors arrived and they're bigger than I expected.


To drive the motors I decided to go with some cheap Chinese H bridges (on their way somewhere on the globe atm). If the cheap H bridges don't work I'll go with the Pololulu DUAL VNH5019 boards.

I've also managed to source a server power supply from work. It's rated at 1300W (106A). I'll hope that it will be enough to drive the two motors. I also found a tutorial on how to get this thing running:
http://www.rcgroups.com/forums/showthread.php?t=1005309#post11639297




Next on my list is to find a seat for the simulator so I can get the measurements for the frame.

Thank you for the information. I'll have to do some more designing on my frame

Thanks. I'll go with 3030 profile.

Does the PSU have an Internal fan ? and do you have a Pinout for it ?

I don't have the pin out for all of the pins, but I found tutorial on how to get it running:
http://www.rcgroups.com/forums/showthread.php?t=1005309#post11639297 (second post)
http://www.rcgroups.com/forums/attachmentNew.php?attachmentid=2356624 (attachement that shows the necessary pins)
The "mod" is pretty simple, all you need is a servo cable and you connect all the wires. Or you can add a switch to it to turn it on and off.
I'm still googling for the rest of the pinout. Hopefully someone somewhere has it.

I have not turned it on yet, because I'm missing a power cord, but I think that there's internal fan. a noisy one as the comment on the rcgroups thread says
"UPDATE 2 These guys are noisy and the only practical way to quieten this particular supply is to slow down the fans by adding a resistor in the supply lead."

The model of the psu is AA23530, part no: 337867-001.

Ok that pin out looks fine, I say fire it up like that and see if the fan are as they say, Noisy, then look into quieting them down, I know the Dell powerEdge 2950 fan's are Loud suckers.

found this little tid bit

"This is my thread on the HP PROLIANT DL580/ML570G3 which is a 12V 1300Watt supply. It's still my favourite for quality, power, small size and having a proper plug for the power cord BUT it's extremely noisy because of the two small high speed cooling fans. Most people will find its vacuum cleaner impression a PIA. Note that you have to take care to identify exactly which supply by the part number. There is a range of DL580 computers with different supplies."

I tried the pins with a multimeter and the grounds seem to be as they're in the rcgroups forum . So I'm pretty confident that I have the same PSU.
I'll have to wait for the power cord to arrive to turn it on. Hopefully I'll get it in a week. We only had power cords at work that attach to the normal pdu's on racks and I'm not confident enough to mod one of those.

If the noise is anything like a HP server turning on, I'll definitely have to look some way to make it more silent.