Showroom Sharo garazhas - DIY Joyrider with e-bike motors + traction loss

Hello everyone!

We are two 20y/o students from Lithuania and this is our little budget diy joyrider rig. It's working but we're adding more features. This is what it looks like now:


The frame was made in solidworks to check all clearances and stability.

Specs:
40x40x2mm square tubing all round except for adjustable monitor, pedal and wheel tubes - 35x35x2mm
2 axis with 350w 330RPM geared e-bike motors from ebay with additional diy reduction via chains
BTS7960 H bridges from ebay
24V 20A psu's
Arduino
3x 21.5" FHD monitors (we had them lying around)
Cheapest steering wheel on the market for testing
Dampers for more precision and faster response (less likely to resonate)
The motors have 9 teeth sprockets, they are driving 44t bmx sprockets for a total of 67RPM

TO DO:
Swap arduino for an STM32 for 20khz PWM generation, because now the motors are audible
More reduction via jackshaft for better response on the sway axis
Wheels for easy transportation
Traction loss simulation
Better wheel (T500RS)
A proper racing seat with 4 point harness
Adjustable ballast (now is a front disk brake welded to the frame)
Paint

Total cost as of now in euros:
Motors - 130 for both
H bridges - 17
Metal tubing, 3mm sheet and 30mm axis - 123
Bearings with housing - 20
24V 20A psu's - 50 for both
Various small tools, bolts, chains and sprockets - about 100
All other electronic components, wires - 120
Monitors were free because we had them
Cheap steering wheel - 30

Total - around 800-900 euros.

Video: https://drive.google.com/open?id=1X3mCvCG3uH-rLSUcWjLrRQsl7bMsW7SM

(2020-09-22)
Big update: the sim is working in its almost final form.
Video:
DIY Bass shaker guide: (to be written)
Changing PWM frequency for silent motors guide: https://www.xsimulator.net/communit...-pwm-frequency-to-20khz-in-arduino-ide.15286/

Very interesting, really well done structure which surprised me the most is the supports of the 3 monitors that are really stable, my support made of aluminum mounted on my 4dof was impractical, it moved too much, so much so that I had to remove it. Steel in this case certainly has more qualities than aluminum.

Thank you! Yes, but the problem with steel is that it is heavy. 7000 series aluminum might work too as its is as strong or stronger than steel, but we didn't have the welder to weld aluminum.

nice jobI like it a lot

Why do you need to change to STM32 for 20kHz pwm? Arduino can do 31.25kHz and 62.5kHz https://forum.arduino.cc/index.php/topic,16612.0.html

BTS7960 H-bridges we are using only support up to 25kHz. 32kHz kinda works but only on light loads, after about 50% duty cycle the bridge shuts down and the arduino has to be reset.

So I am the guy in who's garage we are making this simulator and I came with updates. We want this rig to be as versatile as it can be so we decided to make hydro e brake. This is the first prototype but we are thinking of using car trunk damper as spring so it add "hydro" feel to it.

you guys ever finish this rig as it kinda rocks, and r u running the SMC3 code on the STM32 please

For now we are running arduino nano but we will switch to smt32 becouse of pwm frequency problems with arduino (its very limited and we cant get 16khz - 22 khz on all needed pins)

Nice looking rig. Would like to see this in motion

We have attached video in first post, it shows how everything works, link is https://drive.google.com/open?id=1X3mCvCG3uH-rLSUcWjLrRQsl7bMsW7SM

As your origional post was quite old I thought you might have already changed over as I two have the BT motor drivers and one of those 350 watt motors you mentioned, they do make a bit of noise dont they. But at moment I have ordered a 380kg servo as I have rigged up a 3d printed model of a full 2dof 360 that I got working as of moment with a rotary encoder and small MG continuous rotation servos.

Have you done any more work on your rig as I have watched the video you posted and am very interested in your progress.

and thanks for getting back to me

Well we have done some work, I can post some present pictures of the rig for you. Our limiting factor is money and parts availability, in our country we dont have much selection and shiping from ebay takes very long. Motors arent that noisy once we tested pwm at 20khz, the only noise you can hear is the one coming from chains. Current electric and mechanical design for two axis you can see in photos fits our needs, the main advantage is that its cheap. We are yet to make electronic part of the traction loss system, but mechanical parts is done, we use same engine, same chain and chainring for traction loss as we do for everything esle. Ill come back to you in few hours with more photos of everything.

So big update, our racing seat has arrived. Its the cheapest racing bucket we could find. Also found some 4 point seatbelts.

So here are some update photos you asked for. Second photo is traction loss front pivot point (not assembled at the moment). 4th photo is traction loss wheel at the back, it will spin in both direction and make rig go sideways. We choose this design becouse it gives us A LOT angle (30 degrees to side, but the limit is how much potentiometer can turn at pivot point so its 270 degrees i think )

We also got proper wheel ( T500 RS ). We dint want to go for direct drive becouse in my opinion its overkill compare to real world racing and fanatec is not available in our country. Side engine got better reduction (with jack shaft) so the response of breaking and accelerating would be faster. Reduction of side engine is about 1:66 and for rear engine its about 1:50. Traction loss has also 1:50 reduction and acounting the wheel size it gives us about 1.3 m/s rotation speed. I think it should be plenty for this normal driving, until you spin out . All three current engines are 3000 rpm 350W. Things to do are custom speedometer, we already got the design and all the parts are printed, now we just need to assemble it. We are also thinking of adding heave axis so the racing rig could move up and down but so far its looking a bit expensive. We also need to fit new seat in and figure something out with automatic center of gravity adjustment so our side motor wont have to work extra hard to keep everything level.

would luv to see new video with traction loss working. As for costs I am in same boat as you there, I been planning my build for about 3 years now but keep changing it or change of motor design, then do I go 2 dof 3 dof etc but looking at your rig this would be ideal for dcs world as well as driving so best of both worlds. I sympathise with you on money situation you do have one thing I dont have and thats room. The wait for goods yes same here as most of my goodies come from china. May I make a suggestion about your rig. Why don't you put a pdf or similar together on your build with dimensions etc and ask for a small fee like the guy who made the joyrider I bought his plans, never got round to building one but would certainly buy your plans if price is reasonable. Thanks again for getting back

Well thanks for having so much interest in our project. We design this rig on the go as we both are transport engineering students, I have more practical knowledge the theoretical knowledge combined with my friend. We choose chain driver type because we can get way more angle then any DOF type rig and this design has consistent power and speed at any angle. We cant really share any plans for three reasons. First one is that we make most of the stuff on the go and then calculate it, so we dont have proper plans, only the initial idea has 3D model in SolidWorks. Second reason, its our university project and university will financialy cover all rig cost. Third reason is that our design still has some problems, it flexes a bit more then I would like, its hard to fabricate and some of our used parts are custom made or bought localy (bicycle chainrings and chain for motors). And about buying plans, when we started modeling the initial look, we were thinking it will be hard, but once we started to make it, it became not that hard. This rig is basicly 4 bearing and 2 motors (atleast for now). By the way, traction loss is not finished yet so cant really make a video at the moment and we are not certain that it will work properly because all the traction loss system is a product of my midnight boredom.

Small update, I got the seat fitted to the rig, had to fabricate some custom angle plates so the seat wont be vertical to chassis. It now sits at about 10-15 degrees, feels pretty good. Another thing I noticed that the seat is a little on the small side for me (and probably my friend). but oh well we have to make it work with the parts we have so it will be alright. And also it will be huge weight reduction compared to Ford mondeo seat we had so the rig will be more responsive.

wooow:

it has been a time since i dont see a sim that really likes me... your its grate... i have not read the whole thread, but... i guess that the g forces would be huge!!! some people says that too much movement is not real and that it is more like a parade sim, which i really like

i saw you placed some kind of shock absorbers (2 of them) where did you take them from?

best regards and again congratulations it seams grate!!!

fer