3DOF Full Frame - Arcade Cabinet Build

Today I have started to cut the pieces needed for the Mid-Frame. I’m trying to keep my design footprint small but I want to keep the stability side to side solid. My measurements for this are roughly 46” long by 24” wide. I hope I am wide enough to keep things from being "tippy" when I setup the traction loss.

Workshop is in need of a good cleaning after this.

I have finished the mid-frame assembly. This weekend I hope to be able to finish the bottom frame and get a rough test together for the traction loss setup.

Worked on the base frame and added the wheels to the mid frame today. Hopefully mounting the motors tomorrow and getting a test run going soon.

Very slow progress as I work through some of the details with the motor mounts and the pivot point. I have decided on the height and location of the U-Joint on the mid frame. I am struggling on how to proceed with the motor mounting locations. I will have to do some more mock-up before I am ready to commit to the motor locations. I want things as compact as possible without the motors being too far out in the open up front. And after a few attempts I am getting interference from the top frame with the motors. Lots to think about.

Today I tackled the motor mount locations. I tried a variety of different configurations, and ultimately came up with a design I am happy with. It gives me a small footprint overall and still gives me the leverage I wanted side to side. I still need to build some legs to give me some clearance from the floor for my pivot arms. And I also need to fabricate the connection from the top frame to the pivot arms. This should give me plenty of travel for motion without any interference with the floor, motors, or frame.

Slow going on these last few issues but I want to avoid any costly mistakes so close to the "finish line".

Fabricated the push rod connections on the top frame today. Like all the rest of this process I went down the wrong road at first. Ran into some more clearance issues that I did not forsee with regards to the mounting location on the top frame. I tried to reuse the push rods I had already assembled so I dropped the connection down from the top frame. This ended up being a bad design and did not allow me the clearance I had expected. I then raised the mounting hole for the pushrod up 4 inches and reinstalled them. This looks like it will give me the clearance I need, at the cost of adding 4 inches to the length of the rods.

I am now having issues with the extra drop I added to the original design interfering with the travel. It is binding on motor 1 ("passenger side") push rod, so I will need to cut off the lower arm before I can run a test. Thats what I get for trying to save a few minutes.

I did have some trouble with one of the IBT2's as well. Motor 2 was centering correctly on start but any attempt at moving in the counter clockwise direction caused an immediate jump to the limit set in SMC3 even though PWMMax was set very low. After replacing with a new controller everything works well with the motors disconnected from the rig. Tonight I may have time for a test of Motors 1 & 2 connected to the top frame.

Removing the lowering arms I added to the frame and lengthening the push rods 4" has sorted out the clearance issues. I was able to run a test with the 2 front motors installed along with the seat and electronics in position. I still have not dealt with the traction loss motor as of yet, but That will be dealt with over the weekend I hope.

I do have a few questions about setting up No Limits 2 for smooth motion around "corkscrew" loops as the rig moves from one extreme to the other. I was playing around with settings for Antirollover but I didnt want to chase down any issues that were caused by the old heavy and awkward protype setup. Now that the rig is mostly complete I will be looking into the finer details of the AXIS properties.

Below is a horribly dark video from my basement where this thing will reside. I'm not a good racer but I start easy and push the pace a bit as I get more confidence in the whiole setup. I "test" my Tuning Center numbers and rig movements by intentionally crashing a few times... I swear it was all under contol!

EDIT: Also, I asked in a previous post but I will check again. Is there a way to assign the "Main Level Percent" in the Profile Editor to a phsical knob? I would like to be able to adjust the intensity level from my button box...

Went looking for feet levelers and came up short. Purchased some 1/2" bolts instead and made my own. This will allow me to raise the bottom frame so the front motor arms don't hit the floor, place the electronics and the traction loss motor in this space, and give me leveling ability.

I still need to rethink the top frame, It was the one I started with to get used to welding the material, but I chose 1.25" tubing that was way too thick. It was hard to work with, cut and drill (and REALLY heavy), so I am using it as a template as I move forward with a few changes in mind now that I have seen it all assembled.

But for the next few days I am going to enjoy the machine and tweak a few settings.

I asked in a previous post but I will check again. Is there a way to assign the "Main Level Percent" in the Profile Editor to a phsical knob? I would like to be able to adjust the intensity level from my button box...

Something similar to this for a comfort adjustment for the users.

on the smc3.ino code you can activate the potentiometer in A5 which allows you to adjust the power of sensations.

I will look into that. Thanks for the reply.

Great work ChuckyP! I'm starting my rig now and I'm hoping to get it to work like yours. I also watched DMAX for ideas. Great info!

Thank you. I’ve been lurking here for years trying to learn and get my game plan. And it was also the DMAX videos that got me to finally commit to the design. Good luck with your build, I still need to add the traction loss motor but I’m just enjoying it for the time being as a 2DOF.

Thanks. I'm going the exact same route with 2DOF first to make sure I get things working properly. DMAX's videos are what gave me the courage to attempt my actual build.

I finally found some time to add the final motor for Traction Loss. Im not 100% set on the linkage mounting locations, but what I have at this point gives me equal movement to both sides (roughly 8" total from one extreme to the other).

I am happy with what I have so far so I will be starting to tear everything down soon for final prep and paint.

Here is another update. Just a few small finishing touches and I think the build will be complete. I still need to incorporate the dashboard, the emergency stop and some safety guards for the back traction loss movement so no one loses a limb on this thing. But it has been well tested by teenage drivers and has been holding up well with all the crashing. Here are a couple of videos, one of me driving a Porshe 911 around the EVO Triangle and another showing a closer look at the current state of the build.

Any advice?

I am curious about something:

with my motors being optimal in the 40 degree range (80 total) approx. would I want to set my overall angle to 90 or so rather than the 180 that is default?

this would eliminate the need for any motion cues outside of that range, and also give the software full resolution in the most optimal area to calculate as 100%.

I hope that makes sense. Maybe the software gives for this automatically… I have everything set as 180 currently but that’s been a question in the back of my mind for a while.

So I tore the rig down to fix a broken Traction Loss potentiometer (I think someone kicked it while spectating). While I had it apart I added the brake light mod I have been working on. It is a set of trailer lights in red, they run on 12 volts and I wired them up with a small power supply I attached to the front near the switch on the brake pedal.

It worked out really well. I drilled a hole through the inverted brake pedal assembly and nested the brake light switch flush with the bracket from the other side. I then attached a small angle bracket with an adjustable set screw and nuts to be able to fine tune the reaction of the light with the pedal. The switch is a NC (Normally Closed) design which disconnects the power when pressed and allows the current when the switch is released. As far as quick prototypes go, I am pleased with the results. It is purely aesthetic but it adds some ambiance to the basement.