Home Made 2DOF study/realisation

Hello Everybody!

Before I begin, I introduce myself. I am Nicolas, and sorry for English speaking people, I am French , trying to present my project as I can.

It will not be very special when I see some huge beasts on this forum. Some of you have really astonishing installations!! The idea is to build a 2DOF with the possibility to make it evolve 3DOF and even 4DOF in the future

I am using CATIA software in my job so for the moment, I am currently designing the main frames of the simulator. Here a quite "old" config :

After some research on the internet, I have what I need regarding electronic components thats is to say, SABERTOOTH 2x25A + Arduino UNO + potentiometers + program C language.



I have already done a LEGO model, with small electric motors, to be sure that I will not launch something I cannot do due to electroical mostly (not my best competencies). Hopefully, my C program (Wanegain one, thank you again!) and the link with Simtools is alright then I was like a kid behind the LEGO plate moving following the LFS gaming values

So I really want to thank all the guys which participated to develop this software because it is something I wanted to do for several years and it seems to be possible now thanks to you

I have begun the construction...

Pictures are going to follow slowly (I cannot work every day on the project and I want to work properly )

hi nico...Did you calculate the weight of the whole structure, including you, the tv and the accessories? I say this because from what it is showing, it seems to me that the total there can exceed 250 kg, electric motors rarely manage to push all this.

What motors do you plan to use?

Hi Paulo, Ruba

It is an excellent question! I have also thought about this problem. For the moment, the "suspended" assembly is scheduled to weight 135-140kg maximum, pilot included.
- The main frame which hangs the seat is only 10kg. Will be made with 25x25x2 square S235 Tube.
- I expect 15kg maxi for the seat. I will search it this evening. I practice Off Road Rallying, easier to find some parts
- For the wheel + pedals + gears, approximately 7kg
- The pilot 80kg (yes a strong one )
- Plus rod-ends, links, screws, nuts, welding etc.. I reach 135kg approx

I was wondering if the motors would be sufficient. For the moment, I try to reduce the distance between the CoG of the suspended package and the center of rotation. I think that if this distance (vertical one) is high, the motors are going to b overloaded more easily when there is a change from left to right for example (rolling).
Of course, the center of rotation will be in line with the CoG to be stress free on my engine in horizontal static position.

For the moment I have one motor of RENAULT MASTER II. A french little truck. Working in 12v. Power unknown but seems quite strong. I have begun the installation of the gearing system for the potentiometers. I wanted to have something adjustable, strong and reliable! I do not want to die on my simulator



Do you have an idea of the maximum weight for thise kind of motors? I know that the inertia is an important parameter but an approximated maximum weight can be a good clue

Thanks for your replies and your interest I have done some work already on the motors and for the main structure. I just need to put some pictures and explainations of what I want to do

Hi Everybody,

The 3D model is now well advanced.
The main frames are finished. You can see 4 motors in the model. For the moment I will only use 2 (2DOF). The other one are in prevision of an evolution to have translation + rotation Z axis (vertical).



The seat will be maintained in position like that, using a ball joint at the center. I want to have the possibility to had rotation Z (vertical) later. And also translation Z (the spring is here to limit the loads on the motors and calculated to counterbalance the weight of the moving assembly in medium position. Will need a preload :



The gearing system for the potentiometers. You have the real one in my previous post Ratio x3. The motor support is done using square tube 150x150x3 cut in two halves or a 3mm rolled form plate :


I will base my work on that model to build the simulator.

Thanks to you Paulo, I have reduced the lenght of my "rods" (which actuates the simulator). They were 60mm long, I passed to 50mm to reduce the loads on the motors. I loose some ° of inclinaison but I prefer beginning slowly with the motors

To be continued....

Hi Everybody,

Even if I havent so much answers, I continue sharing my work

Here some pictures of the simulator! After the 3D and 2D, just to follow the plan :










Next steps next time

That's done! The first tests of the simulator have been done and it was so good to see this beast move front/rear and laterally after so much efforts!
The Renault Master I et II motors are strong enough!!


Here some pictures of the construction as usual. I have some videos of the tests but it will be only photos here :

Some modifications to isolate the motors:



Potentiometer ready to be installed:



Seat fixture system:



First non finished installation to test the prototype. The TV is the next step! But it is working!



My brave cousin, ready to test the simulator for the first time (only a picture of the video):


Already some improvements to bring. The rod is too small, there will be more sensations with a bigger one. The motors are strong enough to lift everything so I can afford doing that:



Next step is to test with a real Rally Game!!!

4 small motors will lift all the weight??? wooow

Hi Ferslash! They do not lift all the weight

For the moment, it is a 2DOF. The two motors are just here to create the desequilibrium. The ball joint has been placed just at the CoG of the system counting a 80kg player

Hi 17Nico17! I am very interested in your project. I want to make a similar one too. What is the latest status? Have you added the other motors? And you just uploaded the pictures. Will you add a test video to the topic? Because im wondering how it works. Thanks for the nice information you shared with us.

Hi Huseyin!! Oh la la, I only see you post today... Never seen that I had an answer on my topic.

Yes, of course I have some pictures of the simulator. I came here to see what I added because I am doing some new stuffs and I will integrate the evolution here in this topic
If you still have some questions, feel free to ask if this is not too late.

So sorry to have missed your post...

Some more pictures about the end of the fabrication (see below attached).
You will also find some information inside my post. On electrical warnings and motor information. I share my experience for the new builders
Here some pictures for the "finished" simulator even if these beasts are never really ended^^ always some evolutions to bring!



As you can see, the base was already improved. Normally flat, I have added some uprights to place rods between them and stiff the base. The simulator was so "brutal" it bended the base. The base is 25x25x2 mm square tubing. Thanks to these rods, the base is now very rigid and bring a good plus for the sensations!

After that I have brought other improvements. I had a failure on the port motor so I decided to double the motors. Two per sides. At the beginning the motors were linked by a flexible link. But not very good for load distribution between both motors. In fine, I decided to have a rigid link but with a sort of home made clutch to limit the torsion between the two axles of the two motors and slip if necessary in case of motors rotary speed difference. Also improved the rods to have more adjustement and a better look. All created by hand!

Before and after :



Clutch system, torque limitation controlled by the preload of the springs :



Checking of the complete system.
WARNING : I had many issues with the electricity! Even if I used plastic plates to fix the motors, I had some interferences and this was a problem for the G29 wheel / pedals! Many issues before I understood I had to isolate each motor to be ok with this. Issue on pedals were a non constant feedback and wheel was stuck starboard side from time to time.... I thought it was the TV screeen at the beginning but no... It also caused connexion breackings with the arduino.. I last maybe 30h installing, removing, installing again, removing again the TV screen and everything to understand it was simply the motors.

Here the complete axle system. One motor on one side, the other one on the other side. 4 motor in all :




New home made system for the potentiometer. Better fix and easier to adjust :



Ready to work. Even if I made another part to hang the third point free on the picture :



INFORMATION : Also made some tests to know which motors were the best! Impossible to have these information on the internet. Here what I found :

After many tests to know the motors that have the best torque using a rod and differents weight at the tip of the rod (see pictures below) these are my conclusions :

Best torque I had motor stopped : 28 N.m (Renault Master 1, the less old of this first generation)
Average "good" torque for a good motor : 20-22 N.m (generally Renault Twingo / Clio II / VW Polo)
Lowest torque I had (on the big big motors you see on the picture on the right) : 7 N.m (Renault Master I 1981)

What I seen : generally the more the motor is old, the more it is "weak". Even if you find a very big motor on a 1980-1985 car or truck, I advise to let it, not a good choice. One of the best I have is the Clio II 2003 motor. It is the most little and one of the stringest regarding the torque.... I guess that the age is important because of magnetic properties, but this is just a theory from me.



After many hours of game, I had a failure on a flexible link (black rubber stuff). I decided to mount on rigid as I said above.
After that, no failure for a long time. Just some unscrewing issues. That is why I decide to change the system.

Some information to follow but for the moment with Covid-19 virus, no progress as I miss some material.

Hope this will be usefull for somebody on this forum!! Have a good day

And see you soon!!!

Hi 17Nico17,
Have You try to measure motors from power steering? I just buy one from Opel Corsa B (P20008 GM NSK) but I don't check, yet...

Hi Peter!! I thought about using some, that is a good idea I guess! But to answer your question, no, never used them. For me they are at least as powerfull as the ones for the wipers. If you test them, I would be curious to see the resultas

Hi everybody!! Some news on last evolution of my home made simulator! And this time I guess that this will stay like this as it gives very good results!
Some tips for the ones who could like having some feedbacks on this kind of DIY stuff These are the main changes I did to improve the whole system:

- No more battery => Computer power supply
- Rigid link between two pairs of motors
- No more TV screen => VR Oculus Rift Virtual Reality
- Computer fans under the motors to cool them

With these differences, some questions appeared:

-Is it good for the motors to have a rigid link between them? If they do not turn the same or whatever?
-Computer Power can be strong enough?
-What about the Oculus Rift cameras? Is it possible to have them in move and have the stuff working anyway?
-Computer fans are really efficient?
-What will be the gain regarding the TV screen replacement?

These are the answers:

-I have selected the motors regarding their speed empty. It seems to work just fine after my first hour of use. No special issue.
-I have bought a 42A / 12v power supply on Aliexpress. Around 30€ This is ok to feed the 4 motors. Two pairs have a 20A fusible and the general fusible is 30A. No issue until now. Power supply is not heaven warm after 1 hour play.
-Cameras are strongly attached to the moving part (the one with the driver). When it is moving too hard, some time to time, VR is a bit disturbed. But not very often and this is not so bad.
-Fans bring some air to the motors. Not bad even if efficiency is obviously light. This is better than nothing. I have noticed that motors from recent cars (+2005) are hotter than old ones (1985-2005). I guess that the wires are optimized on more recent motors and bring more heat phenomena. Twingo and Master I french car wipers are almost cold after 30min playing DIRT 2.0 rallying.
-I really advise to remove your screen! Difference is huge! As 10kg of the TV are far from the rotation point, inertia caused by the TV was equivalent to the one given by the driver du to his weight (I do not count the inertia of the driver itself). In breef, simulator is more reactive! And masses are more centered! Like this, when you are not playing, the moving structure does not want to go foreward or backward. This changes the simulator!

If you have some questions, do not hesitate to ask It is very nice to share what we learned to avoid the other members do the same "mistakes"...
Bye! And keep building!

The pictures:

Nice job on the sim.