Showroom 3 DOF racing sim

I finally got to the point in my project where I feel I can post this thread and start my journey to build my racing sim. I would like to start by thanking the all in community for everything that is shared on this website. As I am sure for many, this is where I started with the idea that then spurred on further research. I initially wanted to do a 6 DOF but as I saw more projects and thought more about what I wanted, I seem to have decided on building a 3 DOF "G-seat" for racing with perhaps adding another DOF for traction loss in the future.

My Goal
I plan to build a version of what I have seen called a "G-seat" in which simulates G forces as well as motion. My inspiration on this site would be the likes of @Sielu and others, many thanks!

Progress

Materials purchased:

Motor - (6) 12 VDC 300W 50:1 reduction (I only need 3 at the moment but I bought 6 because I originally wanted to do a 6 DOF)
Motor driver - (6) IBT-2 drivers (2 for each motor); I also purchased some small heatsinks
Potentiometer - (3)6127V1A360L.5FS rotary hall effect sensor
Microcontroller - ELEGOO UNO R3 (these were a bit cheaper and I've used them before on other projects with no issues)
Power supplies - (3) HP DPS-600PB these were modified like the tutorial found in the forum
Couplers - (6) motor couplers for the output shafts found on aliexpress as well as some aluminum flex potentiometer couplers
Linkage - 1/2-20 threaded rod and 1/2-20 female rod ends
Frame - 1 1/4" square steel tubing

Various hardware and tools I already have on hand. There are many things I have yet to purchase but will wait to do so once I get to those points. Some random unforeseen things purchased include wire ferrules, rivnuts, DIN rail terminal blocks, standoffs, etc.

Assembly:

Current steps taken

• SMC3 downloaded to Arduino.
• SMC3 Utilities v1.01 downloaded and port configured.
• Wired up two IBT-2 motor drivers in parallel (the drivers run much much cooler in this configuration).
• Tuned the motor via the SMC3 utilities and things seem to be running smoothly (well after I increased the FPWM to reduce the noise from these motors). However, I feel like there isn't much movement but perhaps I am expecting too much at this point in the project.
• Next area I played with but haven't decided on what I want to settle on is the Clip limit and Max limit.

Next (immediate) steps to take

• Build frame and mount motors
• Determine mounting area for power supplies and controller/periphery

Unfortunately, this will likely be a thread that updates infrequently as I have many other things going on in my life as the likes of many others. Work, children, home projects, and plainly just finding free will be what restricts on my progress. I welcome any comments on improvements, concerns, or just questions in general and look forward to discussing this project with the community.

Looks good, keep us posted on the progress !

in my project, I tried with similar direct coupling of hall sensors first, but then changed to using gears. The increased detail of position measurement reduced jerkiness in the movement and motor noise as well.

What gear ratio did you use?

I went with 50:20, same as recommended in Momolic's guide. That gives full 360 degrees sensor rotation when motor turns 144 degrees (72 degrees up/down). I'm then limiting the motor travel to something like 120-130 degrees with SMC3 to prevent going out of sensor bounds.

Small update (even though it has been months ):
One major hurdle I had to get over was my old computer was so outdated that my Fusion 360 account no longer worked a few months ago and I had to wait to save up and then build my own PC. This has subsequently also improved other aspects of working thankfully.

I finally got the base together in order to mount the motors, however, it still isn't in its final stage. I have a steel sheet I will cut and weld to it in order to make space to mount all the controls and power supply's.

I have designed the control arms that attached to the keyed shaft and have sent them off to be cut by water jet (should receive them this week). I tried different methods to do it myself, but I could ever get accurate results with the tools I have. I designed two attachment points for the lift arms at 70 mm and 85 mm for future preference on movement speed.

The lift arms that attach to the control arms are also complete. I still need to drill out the seat supports that they will attach to and control. That will be a relatively quick step to do though.

Lastly, I have redesigned my potentiometer bracket to incorporate a gear reduction such that it can utilize most of the range of the potentiometer during the limited rotational movement of the motor shaft.

Once I get the motor control arms in, I can assemble what I have done and do a little bit of testing before I start building the seat.

Next steps:
Quick rough assembly and test.
Finish base and mount controls.
Build seat, steering, and pedal supports.
MORE TESTING AND ADJUSTMENTS...

Small update:
Received the water jet cut control arms. Turned out pretty good but the tolerances were a little tight for the keyed shaft which left me with some minor filing. However, when two were installed on the motor I noticed that the keys on the shaft were offset slightly by a few degrees. This meant that the rods on the lift arms (that I precut to the same lengths) would be at different heights at any given point during the motor's rotation. To correct this, I used a level and added some washers inside of the seat frame support so that it wouldn't be cockeyed. The seat frame support really wouldn't care even if I had left it unlevel as it will incorporate a heim (rose) joint at the top of it anyhow, but it bothered me so...
Not much of an update but I do as much as I can when I get a little bit of free time. Once I get a replacement drill bit (broke when drilling out the hole that provides the clamping to the shaft), I can finish the control arms and then move on to the rest of the frame and seat. I also need to add my 3D printed support for the potentiometer to test and make sure there's enough clearance during the desired rotation. I thinking I'll be cutting that close though.

Hi!
good start for this great project

What kind of G seat actuators do you intend to use?
paddles? pressure bladders?

I intend to use paddles.

nice job, can't wait to see more

Well, I have been on hiatus for almost 3 years now but I have returned to this project (having children can really put a pause on personal hobbies). Started dabbling here and there for the past week and haven't done much more than where I left off before. I have the motors mounted to the frame and I cut out some 1/16 inch sheet metal and attached to the frame to act as my mounting surface for the power supplies and terminal blocks.

Next, I'm working on the subframe for the seat with some 2020 extruded aluminum, which will look just like the base frame, and then mounting and terminating the electronics . Once that is done and the seat frame attached to the control arms of the motors, I'll test with Simcalc to make sure things look ok before finishing out the seat and pedal attachment.

I finished the wiring (took longer than I thought determining the layout and making each wire) with the exception of the potentiometer's. They have been assembled to the motor bracket with their respective gearing. It seems though that the shaft of the drive gear that connects to the shaft of the motor isn't coincident and I may need to move the hole up in CAD and reprint. The coupler is a flex coupler so I may end up begin ok during my testing.

I also put together the seat frame. It's constructed out of 2020 extruded aluminum and I'm a little concerned for its rigidity and will likely tack on another 2020 to make it a 2040.

Next steps:

Drill holes and thread the spherical rod ends into the motor control arms.

Cut and drill holes for the plates that will attach to each end of the seat frame that will contain the rods where the spherical rod ends will connect.

Connect the arduino to my PC to test and inevitably fix problems that pop up.

Once testing is good, continue working on the frame for the pedals and the FFB wheel. I also need to determine if I'll just get a fixed seat for now or make the g-seat as originally intended.

Well I thought I was going to post this at least two weeks ago but I ran into problems.

Found where my control arm would collide with my potentiometer bracket, so I redesigned it. Upon printing, it failed a few hours in a 12 hour print and made a mess. Turns out the extruder head broke and I had to order a new part and then spend hours fiddling with it to dial back in my settings (I have an old Creality Ender 3).

Then to make things worse, some very old filament apparently clogged my nozzle and caused different problems. In the end, it is working but I ran out of black so now my brackets are mixed black and silk white...


While all this was going on, I decided to update my control arm in CAD to fix where keys of the output shafts for the motor where not on the same plane. I measured them to be off by 9.5 degrees . So then I had to wait for those to be cut out and mailed by sendcutsend.com. Now the top of the control arm linkages aren't twisted and out of level anymore.

I cut out some pieces of sheet metal I had left from the base (I believe it's 11 gauge stainless) to make as transverse supporting members for my seat frame and then painted them black to try and make it look a bit better.



Lastly, I soldered my wiring to my potentiometers with shielded wire (don't think I need it but had it available) and made sure everything was terminated nice a snug.

I really want to connect to my PC now to finally do a test of all three motors and see this thing move but it's late and I have a sick child at the moment. I'm hoping by this coming weekend I came get it connected and see how things go.

Next steps (once I fix all the issues I find during my test ....) :

Install the seat (ordered and should arrive in a week)
Fabricate the "pedal" frame with some scrap tube steel I have from work (have a decent idea of what I want to do)
Fabricate the FFB wheel mount
Fabricate the handbrake and shifter mount (don't know how I'm going to do this yet lol)

Hi ! This model is great, it reminds me a lot of mine. I was also inspired by this forum. I can't wait to receive the seat so I can sit comfortably ;-) Keep it up!

Sure, does have their similarities. I am currently trying to get my SMC3 settings squared away. Things don't seem to be working properly.

Well, I connect this to my PC and ran SMC3 and things aren't going well. I can get all three motors moving but I have what seems to be a "target" issue on motors 1 and 2 and an overall load issue on all three.

To start, I can't get my bits per second on the com port higher than 128000 bits (seen below in screenshot):

I know that the .ino file shows it should be 500000 bits per second but I don't know how it increase it any higher. However, I can still establish communication and send data.

Target issue:
Next, when running any motion to motors 1 and 2, the target (sent) is higher than the target (received) seen in my arrow #1.

This results in a much smaller movement than what motor 3 gets as the sent and received target are the same (seen in screenshot below).


Load issue:
You can see in the screenshot above for motor 1 my arrow #2 point at the PWM spike and the feedback (potentiometer) lag where I pressed down on the top of the frame to load the motor with some of my body weight and it completely stalls and emits a noise from the motor until the load is released. Is this because I haven't tuned the SMC3 settings properly? Because I don't have the correct bits per second being sent to the arduino? Or is it an issue with my motor IBT-2 drivers? I have wired 2 in parallel to halve the current load each driver experiences (seen in screenshot below).

I know that these motors and worm gear boxes are strong enough for the application. I can connect a 12 VDC battery to one and not even be able to apply enough of a load with my upper body weight to even slow it down. @noorbeast I know you and others have helped troubleshoot with these kinds of issues and was hoping you could give some insight in my case. I can't quite find other threads using the xsimulator search to help self troubleshoot without asking. Thanks for any time you or anyone can provide.