This is something I have been playing with over COVID lockdown. It took a good number of months, off and on, but I think it came out pretty darned nice.
BYOMSA=Build Your Own Motion Sim Actuators
Background: I caught the Sim Racing bug a few years ago, and always felt like my rig was missing something. I even went as far as mounting a low-profile powered subwoofer to the back of the seat to feel road bumps and engine noise, which works really well, but it still wasn't enough.
So I set out to see what was out there to get the rig in motion and I choked on my coffee. 4 actuator systems typically cost anywhere from 6000 to 12000 dollars. Obviously, hard pass. Then I found the SFX-100 project, which can be done cheaper, but requires 2 solid weeks of 3D printing (day and night) to produce parts which are of questionable strength. It also uses some not-so-easy to source and very large, square aluminum extrusions for the body. Interesting idea, and many have done it successfully, but not for me.
So I did the research on what these things are, and outside of the planetary motor types, in their simplest form, they are just a hollow body, ball-screw connected to a servo motor, and ball-nut connected to a shaft with guide bearings keeping everything straight. So I designed my own, which replaces the 3D printed parts with solid polymer sheet parts cut on my CNC router. Two solid weeks of printing was reduced to a couple of hours fine tuning the cutting process. The resulting parts are very strong, and easily resist the actuator bottoming out, with no damage.
I also did away with the extrusion. In it's place is stainless-steel pipe with a much smaller footprint. Easy to source, relatively inexpensive, and it should look good for a long time. Getting a tube flat on the ends was a bit of a chore, but when I was done, I could stack all 4 tubes, with no noticeable deviation in straightness of the stack, or gaps between them.
There are lots of small, but important details in the design, but that's the big picture.
Of course, linear actuators are useless without the motors and driver boxes coupled to a controller. While I was very tempted to start from scratch on the controller part, I decided to just use a canned solution. The Thanos controller, while costly, is out-of-the-box compatible with the servo drivers I used, as well as with the excellent Sim Racing Studio software. Most folks will use a server chassis for mounting all of this, but there was no way I was spending several hundred dollars for a metal box. So I found a department store plastic milk crate knock-off I once had record albums in, and proceeded to modify it, in order to fit this 10lbs of expensive crap into the 5lb box.
If you don't count labor, the total cost of the project was well below half of the least expensive ready-made option with identical specifications. 4 of these had no problem tossing around the rig, a driver, subwoofer and 50" TV, to the point that some of the screws on the TV support snapped. I've since removed the TV from the rig and moved it to a stationary stand due to this. The original setup was never designed to move.
Racing games on this thing are incredibly fun now. Most racing games make telemetry data available to external devices, so pitch, roll, heave, surge, traction loss, etc. are all transmitted based on what is actually occurring in the game. The SRS software has an additional "premium" feature, which allows the system to react to joystick position, but I haven't ponied up the $15 annual subscription fee to try it out. Seems like a bit much to rent usage of an app which appears to hook game controls for positional data, but there may be more to it than that. In any event, the first thing which came to mind for something like this would be to try it out with Space Harrier, Afterburner, etc... I don't know if those games actually produced any telemetry data, but it would be pretty cool if they did. This aspect is definitely on my to-do list, if I can find the time.
Sorry about the crappy photos...