Another 3DOF Build w/ Aluminum Profiles & Wheelchair Motors

Hi Everyone!

Just wanted to say there is a lot of knowledge in these forums which helped me and inspired me to build this rig.

First, I wanted to mention how this journey all started with by trying VR on Assetto Corsa for the first time. I was immediately hooked by the immersion. However, it felt like it was lacking something still. I looked into a motion simulator and discovered DOFReality. Looks like a great product but the price was out of my range. I put it off for a bit, and then one day I discovered Dave from D Max on Youtube. After watching Dave's videos over and over again, I felt inspired to try my hand at building my own. It is still a work in progress as I wait for some parts to arrive. However, the bulk of it is complete and configured in SMC3 Utility.

Majority of the frame is made out of 30 series profiles excluding where the wheel base will be mounted. If I were to do this again, I would probably use 40 series for everything. Using 30 series resulted in my having to buy additional steel flats to strengthen the joints and to add some more rigidity.


Most parts were sourced on Amazon Canada and AliExpress. This rig is powered by H-Bridge controllers and wired up in that little tower case to the left of the pedal setup. I added 2 fans and a fan controller to help keep that case cool. I was able to fit everything in this tiny case. Don't worry, the wires on the right were tucked away from the fans. Also, I would recommend adding thermal paste on the heat sinks of the H-Bridge. I also added tiny heat sink fins with thermal pads on the chipsets.

Some issues I had and solved incase anyone here experiences it and wants a solution or direction on what I did to fix it



Motors will not turn on - Make sure you check your potentiometers. First check the connections are all good. Make sure you are getting proper voltage, I used a multimeter on Voltage mode to make sure the POT is not defective and that it is giving a good output. I tested VCC and Ground to see that I was getting 5V from the Arduino. Next I put the positive lead on OUT and then negative lead on Ground on the POT, I then turned the POT to see if the Voltage output would fluctuate. If so, then the POT is good. After you verified this, go on SMC3, make sure the green line (Potentiometer signal) falls within the Max limit otherwise the failsafe is activated resulting in your motor not turning on.


One motor would not get any power output from the H-Bridge. - I double checked all the connections to and from the Arduino. Double checked with a multimeter to see if there was power going in. Which there was, but no power going out. I swapped that H-Bridge with one that was working and the motor work. Conclusion: Faulty H-Bridge so I bought a new one and returned the faulty one. Just remember, even though it is new, does not mean that it is not faulty.


One Motor when turned on would keep moving and leaving the Max limit set resulting in a constant failsafe. - I reversed the polarity on the power and ground on that motor which ended up fixing it


Unable to get center of balance on U-Joint flange - Because of how close the seat sits by the traction loss motor, I was not able to get the center of balance on the flange. This will result in more load on the motors. One way I plan on alleviating the extra load is by adding some Hydraulic Support Rods near the front. They are about 15" long and have about 67lbs of pressure each. I plan on having one on each side. Stay tuned to see if it helps


Potentiometer to motor connection - I drilled and tapped the center of the motor and added a threaded rod. I tried various ways of attaching the pot to the motor such as a 3d printed coupler(could not get the set screws to hold its place, so it would always loosen), I tried to use a long hex nut and drilled my own holes into it; creating my own metal coupling. The best thing I found to work is just to buy the metal couplings with the correct Inner Diameter. On Amazon Canada, they are about $15.99 for a set of 4. Worth the headache lol


I am still waiting on parts from Fanatec, which is probably the worst customer service I have ever received. Will probably never buy another product from them again. Long story short, the bundle I ordered was waiting on a wheel to be in stock which at the time, was back ordered for only 4 days from the day I ordered based on their website. Few weeks pass and nothing, so I reached out to customer service and they told me that the wheel would be in stock on March 15th, 2024. I asked if I could substitute it for another wheel in stock and they said that I would have to cancel the order and re-order. So I told her to cancel the order and ended up ordering the bundle with a wheel that was in stock. Now I have 2 bundles coming in because the customer service rep did not cancel the order nor will she respond to any of my emails now. Their phone support never answers and their voice mailbox is always full so that is my experience

If anyone is interested in how I mounted my speakers to the rig, I drilled and added a riv nut to it and used a mix of 135 degree and 45 degree brackets around the rig to create that surround sound



The U Joint used




The U-Joint was sourced separately. The flanges were ordered online from a local shop that ended up just ordering it from the states and taking over a month to get. Had I known, I would have ordered it from the states myself to cut the middleman out lol. The joint itself was from Amazon. I ended up pressing everything myself and mounting it with Graded M8 bolts.






Here is the link to the aluminum profiles if anyone is interested. They were purchased off of aliexpress: https://shorturl.at/qSV17 You can negotiate with the seller. I managed to get a few hundred dollars off as well as some extra free hardware. Majority of the aluminum profile and hardware were purchased from this seller.


The motors used were 24V Wheelchair motors linked here. I ordered 2 different types of style of motors as I had a plan on their application

https://www.ebay.ca/itm/323801755153
https://www.ebay.ca/itm/323625070190


Credits:


I referred to this thread which was a great help

https://www.xsimulator.net/communit...3dof-motor-driver-and-windows-utilities.4957/


Dave from D Max for his videos explaining everything

https://www.youtube.com/@DMAX_DIY

Cool build! I'm building in profile as well. Would love more pictures. I'm struggling to get scale. It looks like there is no clearance for the top frame to move.

So sad about Fanatec. Not a whole lot of other options in the space especially since I'm still planning to start with my xbox for a while.

Send me a pm and I can send you additional pics

Ya it is a shame. I read some bad reviews from other people regarding Fanatec but chose to take my chances