Showroom My DIY 3DOF Wood built motion simulator

During 2022, I was introduced to VR, a bit late to the party, I know! I have to say, I was blown away with just how good VR had become.

Having obtained a copy of GT sport on a PlayStation, I decided it would be so much better with a G29 Steering wheel and pedals set up. In my desire for more realism, I set about building a very basic static rig. Having no knowledge of welding, I felt my only option was a wooden construction. I wanted it to be able to fold flat to store out of the way.

It worked well, well enough, for me, that is.

Around October 2022, my wifes pride mobility wheelchair developed a problem, leading to my replacing both the motors. Now having two spare motors caused me to think about my rig? Would it be possible to use these to get this thing moving?

After an initial search for DIY motion simulators, hours of youtube ensued and I couldn’t believe I was seeing loads of DIY projects of all different shapes and sizes, but usually built by guys in their 50s, just like me! Strange that!

After topping up on DMax videos, I set about my new project!

Two wheelchair motors, a sheet of ply, some 3x2 timber, an Arduino uno r3 and a couple of IBT2’s, I was away! ( I Know the IBT2s are not great but this is a tight budget and you have to start somewhere. Upgrades are possible later) bought myself a soldering iron and followed the wiring diagrams.





My first big problem was laying everything out and making basic sketches of the construction. Never having done anything quite like this, I had a basic design in my head but the reality can be different!

One part that worried me was where to source a universal joint. This was easier than I thought. After a brief visit to a local engineering shop, they built one to size while I waited. 20 minutes later, and £60 lighter, I walked out with a fresh new union joint to the spec I wanted.


The motors needed to be solidly fixed. I built a wooden housing using 18mm ply and tied them together with some threaded bar, this definitely made for a more solid construction.

The construction of the motor lever was from a 30mm wide strip of mild steel folded over, drilled through, and bolted onto the motors. Bit of a fiddle cutting the key but slowly does it and it can be done. The bar was from the local Wickes hardware store.



After strengthening the base of the original build with 18mm ply, I built a base to mount the universal joint. I had to lower this base as it was too elevated on first attempt. On my second attempt it looked more like a jenga pile but worked much better.

I went for hall effect potentiometers 180 degree. Sourced those from Mouser electronics in the UK. I positioned these using a 30mm wide aluminium bar connected to the motor by means of some black rubber tubing attached to a 4mm screw that fixed into the centre of the shaft of the motor.



The track rods were made up from 10mm threaded bar with 10mm rod ends attached, encased in metal electrical conduit. I felt the conduit would add tensile strength, being compressed by bolts and washers. Track rod ends from Amazon, threaded bar and electrical conduit was from Screwfix.

The rod ends clanked a bit, I manged to soften this a little by using some rubber washers placed over the top. I did try bolting the washers in but this just limited the movement.
During the construction, I made several changes. I shifted the aluminium bar holding the potentiometers to allow me to switch the position of the crank arms further down the rig. I shortend the crank arm, along with the shift in position gave me much more leverage, it also improved the angle of the crank arm to nearer a 90-degree angle. Whilst this slightly decreased the potential range of movement, it greatly decreased the load on the motors resulting much in better performance and response.



I decided to add wheels to the rig, originally to enable me to move it out of the way, but with the potential for future upgrades.

At this point, i just enjoyed it for a while, well, a week or two. Uploading smc3 and working out how it all worked and interacted with simtools. I must admit, Dmax on you tube was a massive help.
It wasn't long before i started to look at adding more.

Lowering the rig slightly, this definitely helped improve its COG. After a session watching a friend drive the rig quite hard on dirt rally, I could visibly see the 18mm ply bending and lifting on the front right to left. This led to me adding another layer of 12mm ply to the base.

After a couple of weeks of play, whilst my 2DOF worked well, I felt it was time for some upgrades. I purchased another wheelchair motor from eBay for £35, absolute bargain. With the intention of taking the rig to another level with the addition of drift, traction loss or extra 1 as it tends to be labelled.

Since the rig was already on casters, I just added a wheel at the back centre that free wheels on a threaded rod that runs the length of the rig. I felt this wheel would help with stability and ease of side to side movement, and with the rig fixed at the front, this would enable the rear of the rig to track side to side, with the wheel at the rear staying at a 90 degree angle to the centre front position.

I fixed the motor to the side of the rig, this was meant to be a temporary location for testing, but I have grown accustomed to this and it works well.

After the addition of a third potentiometer and IBT2 motor controller, wired into the existing Arduino, a quick setup and test on smc3. This bad boy burst into life. Incredible difference to the experience of the rig!



I have to say thanks to all the guys who have helped me so far, without even knowing it. Its been a great bit of fun. I really wouldn’t have even known where to start without the xsimulator site, DMax on youtube and all the brilliant guys that put all the videos and info out there for us all to enjoy.

Thanks guys.

Already looking forward to my next rig build!!

Hi flipflop,
Great job, its very rare to see 2DOF ou 3 DOF made out of wood, thanks for posting.
I made several plan for wood, but I'm not sure about the measurements.
I tried to make the plans following the design of the rig built by mikeyearly (on youtube)


Could you share some measurements of your rig?
And could you also share the height of the seat support, mine seems to be too high...

Thanks again for sharing your design.
LP

Hi Luis, thanks for your comments, I'm just glad my project was able to help someone.

I will post the measurements tomorrow if that's ok.

You mention the height of the seat post. I must admit, I had to reduce the height of mine. keeping the centre of gravity as low as possible gives the best possible result. That was my finding. It really helps when sway kicks in, as you can end up too top heavy.

I took some videos earlier this evening of me using my rig with Dirt Rally 2. I will try and post a link to youtube link to show how it works. if i can work out how to use youtube!


https://youtube.com/shorts/aXTTLMetoO8?feature=share
https://youtube.com/shorts/EuPodmF8Hgk?feature=share
let me know if that works!!
Thanks

Thanks for replying, it's a privilege to see people doing a great work with different materials

I'm working on the electronics at this moment, 1 motor is working, I will setup the other 2 this week.

Then I will build the box for all the electronics and then the part were I'm going to lose what's left of my hair , then the measures will be very helpful.

BTW: The videos are marked as private.

Thanks again for replying and for sharing your work

I have edited the videos to public. Hopefully they will now work.

Measurements
top wooden frame that the seat, pedals and wheel are attached to. 1340mm x 460mm.

the Jenga looking box frame that the union joint sits on is 190mm high.

the union joint itself is 75mm high.

the total height from the base plate frame to the underside of the top frame is 270mm. from the floor to the underside of the top frame is 460mm.

the base plate frame that sits on 100mm casters is 1010mm x 600mm.

the rotor crank arms had a centre to centre distance of 70mm. (I did try greater but this just created to much force for the motors to push)

The metal trusrod link arms i put together at the front, linking the crank arms to the upper base frame are 240mm centre to centre. (By way of an observation on the rod end bearings. I may have this wrong but the construction videos all suggested right and left hand threads. I get the principle, but, if your using a threaded bar, its all going to be in one direction, either right or left! LOL.)

Just one thing I note on your diagram, I hope you don't mind me mentioning. the upper frame construction. If it is going to be wooden, then I would say you will need a plywood base in it rather than just a timber frame. the twisting forces on that, will, I think, rip it apart. I would suggest that be at least 18mm ply too. that would give it rigidity. I know it will increase weight, but I don't think you will have a choice.

One other thing I found worked well, is the attachment points either side of the frame that the linkage bars connect to. I found using a threaded bar right the way through the frame, so it came out either side, for the rod ends to attach to, rather than just bolts. this helped prevent a twisting motion on the frame too.

Hope that helps.

The videos are great, so much movement

I welcome any tip, specially before the building process ,and you should be right, the forces applied by the motor arms should require a stronger structure.

I will also consider putting some metal bars across the frame. I have some wheel chair motors, let's see what they can handle in terms of weight, I think that the distance between the center of gravity and the motors is enough to avoid motor from getting overloaded.

Thanks for so much information, I will to use it all

Hi @flipflop,
Are you using the batteries to "fuel" the motors?
I'm building my "brain\electric box" with 3 power supplies, one per engine, in your opinion, is the battery option, a better one?

Thanks,
Luís Pinho

Hi, I used 2 * 12v batteries from a powerchair wheelchair.
They produce plenty of power for the three motors giving hours of use. I charge them every couple of weeks.
My reasoning on using batteries was, first, its a simple low cost solution, and since I had them out of an existing powerchair, they didn't cost me anything.
Secondly, I looked at using the power supply route or a server psu and my concern was the regenerative voltage that comes back from the motors. I believe this needs a battery in the system to absorb that. I think it may be called back emf?? This, i am led to believe, can blow your circuits to pieces

So for me, using batteries was the simple and least problematic route. Just make sure you install an inline fuse.

I am beginning a 6dof build, and so considering using 4 * batteries to drive that, 2 batteries for each set of 3 motors. Not sure if I may even need 6 batteries to Power 3 sets of 2 motors.???

This may make me change my mind about using server power supply units

https://www.xsimulator.net/community/threads/how-to-modify-a-server-power-supply-for-12v.5774/

This might be an interesting option for the 6dof build

Wow, 6DOF, will you be using motors or actuactors?

Will you still be using wood?

Thanks for the advice

I managed to get hold of some pretty hefty sunrise medical wheelchair motors that I believe would be up to the job.

I looked at a wood build, which I quite fancy the challenge of a wooden Stewart platform

But, I think I might ultimately have to go down the welding route.

I was thinking of a wooden prototype first, just to get my head around everything.

That looks like a fun project
I think you would be the 1st to make a 6 DOF made out of wood.

Do you think 15 mm is enough for the ply wood, its hard to find 18 mm with enough length for a good price.

I could renforce it with rectangular steel tubes beneath it, under the edge of the top part of the rig.

What do you think?

Thanks for the help

Shout out to all wooden motion sim rigs!! If you build it correctly it can take a tremendous amount of force. the vast majority of my wooden 3 DOF is just 2x4s. I am going to build a 6 DOF out of wood as well but we would not be the first, I believe SilentChill build his first 6 DOF out of wood about 8 years ago.

You should be fine with 15mm. I just wanted to ensure it was strong enough to take the twisting motion that you will experience going through the rig.

Congrats on a great wooden build, where all motion sims should start.

Hi @flipflop just wanted to thank you, I'm on the final stages of ending my build, inspired in your build.

And as I finish, I now understand why your motor area width is less than the rest of the width of the middle layer, I'm so stupid .

I mounted the motor right on the edge, so my arms are 10 cm away from the frame, I will have to redo this...

I noticed you went down the power supply route.
Can I please ask,
How are you finding that? What power supply unit you went for? do you feel they are delivering enough power consistently?
Thanks