Showroom Bolt-on 2DOF project with 12V600W motors

After studying in this site for serveral months I started building my 2dof recently.
There is no sim rig DIYer around me so it cost a lot of time for me to find the right material from your hints and projects, thanks for Xsimulator and all of you.

The building was based on my static rig that I built last year, it was all made of extrusion aluminum bars and used standard bolts and linkage parts， I‘d like to keep this style in the dof building to lower the cost and set a easy-to-make model for others.

The first step for the conversion started with motor selection, as all kinds of common motor are made and available in my country(China), I decided to choose new ones with reduction gearbox instead of wiper motors.
The finally result is this 12V600W 45rpm motor (it was sold as power sourse for fertilizer mixer), I doubt it could reach its rated output but because of its powerful looking size(motor dia.110mm) and price(only like 18USD each), I gave it a try.

It has a hexagon(s=16mm) hole for shaft, in order to avoid cost for custom-made parts and welding, I worked out that ultra long M10 nut could fit right in(a thin shim was inserted to fill the play), its inner thread could also make lever and potentiometer fixation easier.

This is the final motor sub-assemably.

potentiometer side: M10 φ5 hollow bolt, φ5 knock pin, φ5xφ6 coupler
lever side:M10 bolt and nuts, antislip washer, 3mm thick linkage plate as a temporary lever

For motor fixation I used 8 I-linkage plate to mount it on to the frame with both sides of its gearbox, it's a bit ugly but an only 1 dollar solution.
Actually I draw a one-piece mounting plate for this but the material and laser-cut would cost me around $10, so abandoned.

Next, the joint for seat, I might have overlooked the required strength and ended up with this heavy duty one, as I saw others' projects only used ones with diameter of human wrist. But since it's only $15, let it be.

Later when I was designing the mounting for this joint, it turnd out to be the right and lucky choice.
Still, to aviod welding process. I made a minimum size “曰” frame with 40 aluminum and standard L-linkage, it turned out the flange of the joint can fit right throught the structure, look how close the clearance is.

For strength and compactness, I chose to use laser cut SUS plate to mate the joint to frame. one for upper with 6mm thick and bottom one 8mm, material & cut & freight cost $28.5.

With all these arrived I assembled them to the this current status.

bucket seat mounted on

To be honest not many movement calculations were made yet, the roll and pitch angle given by the lever of the motor and other dimensions may need a fine adjustment, but since the structure is easy to disassemble and modify, I'm still optimistic.

And for electrics, I've already tested my 220vAC~12vDC(600w) PSU with the motor(although no-load), and I have connected arduino board with IBT43A and potentiomter, from the SMC3 Utils everything turned out to be fine.

I will keep updating the building process, any comments and advices from you will be grateful, thanks!

Nice one. One thing to note is the seat position. It is much higher now so will loose GT driving position style. Maybe try to lower it. I would use thicker wires since it is then 50A rated motor.
And use diode to protect power supply from tripping. For kill switch use circuit breker for 220V or 110V depends of your country.

You can see here some pictures of my design https://www.xsimulator.net/community/threads/simlab-gt2-to-2dof-conversion.13948/

Good luck.

Thanks iLLuac, I've read yours, our projects have many features in common, it inspired me a lot.
I will take care of the power lines.
The driving position plan has not been mentioned yet: I'm considering to fix pedals & steering & monitor with the seat，let them move together will give a more immersive experience I think.

Sorry but an IBT-2 motor driver is likely to fail with that wattage motor unless you can run okay using much less than full voltage when loaded.

Side note, if paying with USD in the USA you would be paying at least 4 times as much.

Yes, clearly IBT-2's 43A is no sufficient for 600w under 12v, but there are complains on the motor's page saying the actual power is around 400w, if it would fail under load I will try using one monster moto board(30Ax2) for each motor.
Can you suggest any other driver board which can handle a higher current?

Also thanks for the side note, 4 times! there are indeed quite some advantages for DIYing things here.

I think you will be better suited with ibt2 than with monster moto board especially since there are many clones that are really bad and original one are expensive. The other option is sabertooth that is even more expensive.

More expensive yes, but think of the money you will save on hair transplants. .

Hi guys, as you remind me the motor driver capability, I did some product search and further studying on the H bridge driver. And I found this:


This is a Chinese company made motor driver that is capable of running 2x60A(rated), max 160A for each motor.
Input voltage: 12V~30V
control: A1.A2=0.0 brake, A1.A2=1.0 CW rotate, A1.A2=0.1 CCW rotate, PA=PWM input(up to 60kHz,duty~98%), same to motor B
*And its price is only $27, much cheaper than sabertooth(in here one 2x60A sabertooth costs $285)

From what I know, this is quite the same pin and control method as Monster moto sheild, I think it should work with SMC3, am I correct？

PS: this company even has a option of 100Ax2, for $42.5

Here is some progress I made today
·the second motor is mounted
·made a temporary rod connection(made of exsiting material) to have a brief check the movement range and stiffness
⇒the seat is very steady, when unpluged, the motor won't be cranked by my weight



the brackets for potentiometer still need some modification
then hopefully the test on SMC3 can be conducted.

as noted a diode is needed to protect the power unit.
I bought an anti-backflow diode, today it arrived.
Spec:100A 1600V
price: 31 rmb=4.4usd (diode=21,heat sink=10)
thermal grease has been applied by the shop
looks good I should order another one.

And the most intriguing thing, Chinese made 2x60A driver board(27usd)
not much bigger than monster sheild, the soldering on the back is amazing
relatively simple 5pin layout(5v,Pwm,enable1,enable2,GND) for each motor.
I have tested by the SMC3 mode1 setting, it worked fine as I expected, I will attach a video after




can it be a substitute of sabertooth, need more thermal test with full load

here is some wiring photos when I test this board
same as a monster moto shield
I will attach some thermo couplers on the fins to measure its temp under load.

◆Recent update:
・added one 60A breaker for each motor
・added a volt/amp/watt meter to monitor the motor
・wired with one motor with all electric elements and ran a Sine wave motion test with load(my weight 80kg)

◆Results and new issues
・The watt meter doesn't have a quick enough sampling rate, the highest watt reading is only 70W, which I doubt.
・The Chinese driver board can handle this load with ease, no heat felt on the sink after 5mins(ambient temp 10 celsius)
・The lever(sway arm) on the motor is not rigid enough(and the only weak point), I'd have to double the lever plates

And this is the componets

Today
1)I enforced the motor levers(by doubling the plates),
2)In order to fix pedals with seat I replaced two longer longitudinal beams

Hi SoftKitty, your project looks very nice! Initially I wanted to build a 6DOF, but as I have zero experience with motio simulators I will start with a 2DOF. I will be following your progress to cheer for you and learn a bit.
Where did you buy the universal joint that you showed on the first post? I tried searching online but I can only find small ones for robots.

Hi, BrazilianGuy, thanks!
The joint link was https://item.taobao.com/item.htm?spm=a1z09.2.0.0.39592e8dmqnzjy&id=579749981009&_u=82jb9e952b3
※there are several options on this page, I used"6孔120圆盘耳孔35总高126定位70"
But I'm not sure if you can access Taobao.com in your country, or they can ship the item to your location.
adding keywords like “propeller shaft”,"industrial" in your search might help.

Here is a 3D printed potentiometer bracket.

The steel one I post earlier is 1~2mm off the center,
which puts a lot of sheer force on the coupler.

After the work at this weekend, it finally revealed its shape.
Some adjustments will be done after I mount my wheel and pedals.

The joint seems to be too much behind the seat,
I think it should be right under my thigh, to match the pitch center of a real car(right?)
but it can be easily tuned because it's all bolted on!

Theme for next week is electronics.