Wooden full frame 2 DOF/ 3 DOF / 4 DOF

Hello, my name is Adam. I have been lurking on this website for quite some time now and I finally decided I NEEDED to have a motion sim. 8 months ago I built a wooden 2 dof full frame motion simulator with wiper motors from 90s ford trucks (pick and pull) 2 random tie rods (same junk yard) and a steering shaft u joint. This later evolved into a u joint/driveshaft from a Toyota pickup and 2 motors from a mobility scooter along with an upper frame redesign. Here is my journey... sorry I didn't take very many pictures

My first job was to ground isolate the wiper motors and it was one of the most difficult. These motors have a shaft that runs all the way through the motor housing but is connected to the "cap" along with the magnets. All this boils down to the fact that brushes don't come out with the cap but the shaft does so the brushes shoot out of their housings (spring loaded) when you disassemble the motor. After removing the ground to case I had to figure out how to get the motors back together. I ended up using sowing thread, tied around the wire connected to the brush, to compress the springs and keep the brushes held back so I could reinsert the shaft/cap combo. After it was inserted I cut the thread to release the brushes back onto the shaft. I also removed the slow speed brush from the motors.

Next I wired the electronics, an Arduino and a Monster Moto that I purchased some years back on a false start attempt at building a motion sim, but the MM failed immediately. The motors twitched once in SMC3 but never actually ran. I bought some IBT-2s and a couple new Arduinos ( I burnt the original one because I didn't isolate it from my metal case I housed the electronics in...) and wired them up in an old dell power supply case I gutted. I works!! The motors turn!

It took me an embarrassing amount of time to under stand that the potentiometers will stop the motors from spinning if you actually connect them to the shaft. I couldn't understand why I couldn't stop the motors when I tried to put it level with the center line in SMC3 but it was supposed to?!? That's when I learned about the preciseness of a hall effect potentiometer. So once I hooked those up to the motors using a ton of hot glue and rubber tubing and oriented the motors correctly I was all set to build the frame.

I started building the frame by making a basic rectangle from cheap 2x4s and added braces where the u joint would mount and where the motors mounted. I covered the front portion with a sheet of plywood. I mounted the the steering u joint to the lower frame and mounted the motors with L brackets from Home Depot.

Since I wanted the upper frame to be light I decided to go with a single 2x4 as the "spine" that I would mount the seat and connecting rod cross member to. I got a seat from a Honda Insight, mounted it to two 2x4s and mounted that to the spine. I screwed the spine into the u joint and screwed the connecting rod cross member into the spine. I mounted the connecting rod to the cross member with the short fat L brackets from Home Depot by drilling a hole in the center-ish of the three screw holes where I inserted the connecting rod end.

I dont have pictures or video of the first attempt with the steering u joint because it collapsed almost immediately. There was no yaw stabilization with such a weak u joint. Instead of building a yaw stabilization rig I just went to the pick and pull and got a rear driveshaft from a Toyota truck. That solved the yaw stabilization issue.

Here is the first test:

Here is a test flight in War Thunder before I built the "dashboard" for the steering wheel:



After I built the wheel mount, testing in Asseto Corsa:



Here is a walkaround of the rig with everything mounted:




I added the new motors (ElectroCraft MPS32) but the CTC was too much and was shutting off the IBT-2s under load. I realized I needed to rebuild the whole upper frame because it was too unstable:

At this point I rebuilt the upper frame as a matching rectangle to the lower frame with several cross braces - 2 for the seat mount, 2 for the u joint mount, the same connecting rod cross member and a cross brace for the pedal mount. This stiffened the fame substantially and now I have a solid rig. It doesn't have a lot of movement but the movement it does have is fierce!

My motion simulator has been missing something as of late... Traction loss! I designed and built a new lower frame, sourced 3 caster wheels from a couple of electric wheelchairs (one for the pivot and two for the mid frame to ride on the lower frame) along with a motor and grabbed another connecting rod from the junkyard. Before I started this build I decided to move the motors and the connecting rod crossmember back towards the U-joint to get more actuation from my lever arms. I will also try converting this to 24V to see if there is any difference.


Starting the build:



Working on the middle frame:



Lower frame built and casters mounted:




The completed rig:

Here are some miscellaneous videos that might be of use -


IBT2 testing:



The welds break on my 3DOF:



I learn about welding:

Here I am drifting in Assetto Corsa. I moved the potentiometers to the rear of the gear box so they cannot be hit by the lever arm/ connecting rod (zero interference). The potentiometer tubing is still fresh in this video so the tracking is still accurate. The tubing wears with use and it keeps throwing the position of the pots off. I have started to learn 3D modeling so I can print my own pulleys to replace the tubing method.

I added power switches to the rig because I was tired of having to bend down and connect the terminal to the battery. I would also have to remember to put the battery on the charger when I was done with the sim, now I can leave the terminal and charger connected at all times. I also added the 4 point harness to the sim. To do so I needed to modify the seat since it did not have a space for shoulder belts. I unzipped the seat and cut away a bit of the foam to expose an iron bar that I would use to loop the shoulder straps around. I also had to cut slits into the front padding of the backrest and I used a heated box knife to do so. I used a lighter to heat the knife edge and when it was hot it would cut/melt through the fabric and padding easily. I used this method in an attempt to keep the fabric from fraying and unravelling. I then used 2 bungie cords to connect the belts to the mid frame.

I created a wind simulator for the rig using 3 inline blower motors. I used 2 arduinos and 2 monster moto shields along with the simhub software to get pretty powerful wind sim. The first Arduino/ MM has two fans, right and left, and the second Arduino/ MM had the third fan, center. I want to try and build another wind sim using IBT-2s and the code for simdash.

I tried to record directly from the headset and quickly learned why I dont see people online making content like this. Its tough to watch since it just bounces around too much. I am going to learn how to pull replays from AC and PiP with the recording of the rig.

I've always wanted to try running the IBT-2 (BTS7960) in parallel and I was having issues with the motion sim rig so I decided now was a great time to try it. Here I go through how to setup the IBT-2's in a parallel and I install them. Once installed I started having a lot of issues with the electronics. I didnt figure it out in this video but Im getting closer. I also show the wind simulator installed on the rig, all 3 of them. Later I hint at a possible new motion simulator using 3 mobility scooter rear-ends and a little update to the Gseat:


I finally figure out the issue with the electronics! I say the wire was melting in the video but it was very little on at the end. My major issue was combining the negative wires from all the motor drivers into a single wire that I connected to the negative end of the terminal. I fixed this by using thicker gauge wire and running the IBT-2s individually to the negative terminal. After I figured out that gremlin the motion simulator run perfectly now. I also decided that I needed a driver side door since I did not want to make the throttle mount removable. The throttle mount made it very difficult to get in and out of the rig coupled with the fact the rig is so tall now.

I am converting my 3 DOF into a 4 DOF by adding the addition of a surge axis. I was inspired to do so after seeing Kevinski/ DoctorADHD1 amazing 4 DOF design. I hope you dont mind me butchering it a bit but I have to work with that Ive got. This surge axis concept has lived in my head rent free for the past week so I decided it was time to start the modification process.

I want to rebuild the lower frame (traction loss) to lower the height of the sim overall. I will need to modify the swivel joint at the front and I will be using different casters so that all will need to be redesigned. While I have the sim apart I will rebalance the upper frame, that has not been done since I first rebuilt the upper frame, I will be cleaning up all the rough edges and painting everything.

I wanted to document the process a bit more so I am showing the materials I am using and how I need to modify them to make it work for my purposes. I started with the two "trolleys" that the upper frame and pitch/roll motors will mount to.

I created the 2 rails from 3 equal length box tubing cut in half. I beveled the edges for welding and tacked the rails together. I measured the distance between the rails with another shorter box section that I cut into fourths, cutting each face free. I then tacked the rails to the "beams", one in front and the other in back. I then welded the tacked section of rails together and grinded them smooth

Next I needed to add the bearings to the trolley rails so I drilled out holes on the angled section for the bolts to pass through and bolted on the bearings. I am using 2 different size bearings because that is that I had so I will need to adjust for that difference in the design. The back trolley has 8 638rs bearings and the front has 8 608rs bearings.

I set the 4 trolley rails on the riding rails to set their distance and make sure they were oriented correctly to the track before tacking them to their bases. Lastly I cleaned and assembled the motor the was full of grease and mocked everything up to see how it will look and function.

Since I am not mounting the rails like Kevinski / DoctorADHD1 (aka the smart way) I will need to drop the height of the frames significantly. I plan on completely rebuilding the lower (TR) frame, mounting different casters in the rear, and modifying/ replacing the swivel joint at the front.

In addition to this I want to possibly modify the mid frame and U-joint height. This will be quite an involved process that essentially just lowers the pitch/ roll motors but I could possibly move them inboard instead. Moving them inboard will give me the benefit of more roll at the cost of more torque so I think I am going to look into that first. The other method would have involved modifying the mid frame by cutting it to farthest point back in the motors travel on the surge rails and then making a thinner section for the rails to mount to. So essentially the pitch/ roll motors would "sink" down into the mid frame as I modify the height of the U-joint. I am going to think on this more...

Thank you Beast!

I wanted to post a quick video of me load testing my IBT-2s. In my first IBT-2 testing video I show how to verify the IBT-2 will power up and work in both directions. This was done with a 12v power supply. The next step for testing is to verify it will work with 24v and to see if/ how long it can lift 40 lbs on a 7 inch lever arm.

Hey mate. I didn't realise you were on here!

If you wanna stand on the shoulders of giants you must travel to where they live.

Drifting in Assetto, lighting is on point... Last video before I tore the 3 DOF down to mount to the Surge rails and trolleys.


Here I redesign the rails after realizing that the rig WILL derail without a capture bearing. I also redesign the trolleys and rail mount.


I mount the surge rails to the mid frame, weld the U-joint to its trolley, mount the motors to their trolley and mount the top frame. Everything is sliding now! Everything is built using recycled materials from electric wheelchair and scooter frames, which means there is a lot more consideration that goes into the design. You are essentially building a puzzle but you have to build the puzzle pieces first. You need to be able to see them hidden inside that pile of "junk" and then extract them by removing the excess. I believe it is the same skill a sculptor uses to see David in a slab of marble.