2DOF Build Log Thread

Hey everyone,

I'm starting my build thread as recommended. My plan is to build a standard 2DOF platform mover sim using gearmotors for racing/flight sims. My main priorities as far as the build goes are:

1) Have the rig be fast/responsive (more optimized for simracing than flight, but able to do both).
2) Keep cost moderate to low (I'm a student and my budget is fairly tight).
3) Keep the footprint of the rig small.
4) Make the rig at least a little bit aesthetically pleasing.
5) Leave the option open to add a Yaw axis to the rig later on.

Keeping all of this in mind, here are my plans as they stand now:


As far as parts go, here's a tentative list so far:

Mechanical:
Mechanical design and assembly is not my strong suit, so any critiques/advice is welcome.

Motors:
Either: http://www.ebay.ca/itm/351093944483
or
http://www.ebay.ca/itm/GEAR-MOTOR-1...256511?hash=item567baf0a7f:g:H6oAAOSwQPlV-rtb

I'm not sure which ratio to go with. Advice would be appreciated

U-Joint:
http://www.ebay.ca/itm/381119652601

This seems like a good choice. I see a lot of other people salvaging U joints from other sources, but I don't know I'd go about doing that.

The Frame:
I have a little bit of welding/machine shop know how, so I'd be doing my own construction.
The frame would most likely be made of square steel tubing, although I really don't know what size it should be.

Motor Arms:
The main arms I can simply mill out of steel, but I need help finding suitable ball joints to attach both ends of the actuator to the rig. I would greatly appreciate advice in this area.

Misc:
http://www.ebay.ca/itm/262010478925 Flexible couplings for pot mounts.

A seat. I cannot for the life of me find someone who will sell me a single used racing seat. I'm constantly scanning kijiji/craigslist but to no avail.

Motor Mounts:
I still need some way to mount the motors to the base of the frame, I don't know how easy this would be to do myself.

Electrical:
I'm an EE student by trade, so this is definitely more my stomping ground than the mechanical portion. I'm thinking of designing my own driver board once I get the main rig up and running.

Power Supply:
http://www.ebay.ca/itm/351299826035?var=620448663996
The 12V 50A 600W version of this (overkill, but I want to leave wiggle room for adding a yaw axis later down the line).

Controllers and Drivers:
While I've heard great things about the JRK driver/PID controllers, it's just not within my budget to blow $190 on two of the boards. I'm opting to use an arduino as a controller (I already have one) and use the VNH2SP30 boards (with heatsinks of course) to deliver power to the motors:

http://www.ebay.ca/itm/310780916584

Rotation Sensors:
At the start I will most likely just be using single turn pots, however I may upgrade to a hall effect sensor in the future such as:

http://www.digikey.ca/product-detail/en/6127V1A360L.5FS/987-1393-ND/2620662

Again, looking for advice/criticism before I pull the trigger and start buying this stuff.
Thanks

Hey @Tim McGuire you said "Hey everyone, I'm starting my build thread as recommended. My plan is to build a standard 2DOF platform mover sim using gearmotors for racing/flight sims."

And I suggest not to build a motion platform if your favorite game is any racing simulation (seat shaker or mover). If you like flight simulations and you race only rarely then you should go the motion platform route.
Regards
Pit

@noorbeast thanks for the additional information and details I was writing this between the sheets after waking up

So as @noorbeast said. Seat mover for race , but a foot motor mount full frame is good for race if the movements are nice and short and sharp.
You may need to decide what overall you intend to play.
And if its full frame , shoulder mount at rear or foot motor mount at front. For what you have in mind is not recommended.

Thanks for the feedback guys.

I've considered doing a seat mover, but since I will be playing some flight games (Elite Dangeroud, EVE Valkyrie when they come out), and trying to integrate a VR headset into the design when they come out, I think a full platform might be better for me. Honestly though I'm not even 100% sure about that either. Worst comes to worst I figure it's probably easier to take an angle grinder to a full platform and cut it down/make some modifications and turn it into a seat mover than to do the opposite.
As far as shoulder mounting goes, I know it will give my much better lever angle, but won't that make the torque loads on the motors uneven in the pitch/roll directions? I was under the impression that this was important.

You sure u got that @ right ? Lol

Shoulder mount at rear on a full frame can give you appropriate angle. I did a full frame shoulder mount for a mate a while ago, 60:1 boxes 80mm CTC levers, he gets about 18 deg total angle .

Right, I'm not too worried about total throw angle. More so the fact that if I mount the arms farther rearward from the pivot than they how wide they are mounted, wouldn't that mean that the rig would move faster in the pitch direction, and slower in the roll direction, given that the lever angle for the pitch is now greater than that of the roll?

That sounds interesting. Do you have a build thread for it that you could link me to? Or a few pictures?

Thanks! Well I guess there's no more putting it off, I'm probably gonna have to start buying stuff soon :|
I'll make some tweaks to my CAD files and post them here later on

The speed difference between a bigger roll and smaller pitch , for example , is negligable. My Desk Racer of which noorbeasts DX racer is based off has 7 deg roll but 17 deg pitch. And as said, a good profile sort and it all feels even. The actual speed time difference would be in the fraction of a second. If you can notice that then you are doing better than me.

So something like this would be more recommended?

Also where do you guys normally go about getting your U joints from?
And what kind of shaft do you usually attach the ball joints for the motor arm onto? How are they usually attached?

I go to a car wrecking yard and ask for a cheap rear wheel drive car tailshaft.
Usually costs me $20-$30 so shop around as some places want too much money
I cut it to length and weld a plate on the end for bolting it up

Perfect, thanks! There are a few wrecking yards around where I live