2dof + Traction Build.

[bodgy]

Hi All,
Lurked these forums years ago but everything has come a long way and simplified since then so I think I'm going to make an attempt at a simulator. Hoping to build a 2 dof sim with drift/traction loss.



Plan so far:
(Things already around the house)
*40 amp 12v caravan charger.
*35ah agm battery.
*One 'big motor' 12v worm drive from a broken electric golf caddy. (second worm drive was damaged so only one working unit).
*Logitech MOMO wheel and pedals.
*3d Projector. (waiting for my glasses to be delivered)
*Racing seat, free from a mate if he can find it.

To order:
*Unsure weather to bite the bullet and go with JRK controllers (3 x $100 + shipping blows the budget out a bit) or try an arduino set up. I have limited experience with programming so the JRK units are looking more attractive.
*Hoping the worm drive motor I already have can operate the yaw axis and go with wiper motors for chair actuation. If not order 2 more worm drives or search the junkyard again.
*Would like a tactile transducer setup. Probably 4 dayton pucks.

I have been toying with a design in my head that manifested itself in google sketchup this morning.
*It basically centres around a brake disc that is mounted on a stub axle welded to a lower frame.
*An upper frame would mount to the brake disc and would hold the chair actuating motors.
*A uni joint would be welded to the hub and the seat etc would be mounted from there.

Sim Frame 1.jpg (242.26 KiB) Viewed 13389 times

Brake rotor sim design.

Sim Frame 1 hum.jpg (432.21 KiB) Viewed 13389 times

Brake rotor sim design 2

Sim Frame 1 dfg.jpg (270.39 KiB) Viewed 13387 times

Brake rotor sim design 3

Any ideas/criticism? Would love some feedback and links to similar designs. Motor/linkage placement is just for conceptual purposes and would obviously need adjustment. My real concern is the brake disc as a pivot point i suppose.

Cheers.

[mario318i]

Hi bodgy!

I´m also planing my second racing Sim with 3 Motors.

I also wanted to use the JRK`s like in my first SIM, but they get really expensive, when you need 3.

So i was going to use the arduino edition: Arduino MEGA; 1 Double-Motordriver and one single!

Total Cost of this setup: 160€ instead of 350USD for the JRK`s.

Hopefully it works .......

Best regards

[yokoyoko]

Hi,
using the big motor for the tl sounds good. The wiper should be fine for seat moving. I use a wiper for my tl too and it works really well. But more power should give you some reserve for more motion of the tl. I only use 15cm+15cm (feft /right) at the moment.

Perhaps you know my thread? If not please compare our both designs. I use a distance between the front bearing and the seat. This inertia (in the seat) while rotation gives the immersion in my opinion. I don't think you will feel a lot with your planed design. You sit on top of the bearing - in a real car the rear axis "rotates around the front wheels" when traction is lost. I would use the bearing where you expect the front wheels in your simulator. Of course you would need a second bearing in the rear...

BUT this are just my thoughts and we are discussing here

edit: added link to my traction loss topic: http://www.x-sim.de/forum/viewtopic.php?f=37&t=289&start=60 .. + some deatiled video on page 8

@ all --> I think it would be generally very loyal to post his projects only in the forum where you use the software from ... but of course everyone is free to do what he believes to be right. no criticism

[bodgy]

With regards to cross posting on both forums it's a pain and I wish i didn't have to do it but I just want input from the most people I can and if this is the situation that has been created so be it. I have no idea why there is this forum split but I am interested in the 'new software' being tested there so will continue to post on both. Sorry if this offends anyone.

I had a look at your thread yoko but found it a bit hard to see what was going on with the pics. I will look at the video when I have time and decent internet access (I have limited data as I tether from my phone - total pain in the ass to use with x-sim btw.)

I get what you are saying about maximising the felt force by moving the pivot point forward but like you said that would require extra support at the rear and I am trying to keep this as simple as I can. I had a rethink and was wondering what people think about this pivot design trying to maximise movement. Too much for a worm drive or winch motor to handle with the extra load closer to the axis?

Sim Yaw Design.jpg (137.81 KiB) Viewed 13221 times

Sim yaw design.

Sim Yaw Design 2.jpg (134.07 KiB) Viewed 13221 times

Sim yaw design 2.

Cheers.

[RacingMat]

Hi Bodgy !

nice to see your beautiful drawings : it makes the subject clear !
the brake disk is interesting but I would see two drawbacks :
- how you will lubricate it ? for this rotation, a ball bearing woul be more appropriate, no ?
- I agree with Yokoyoko, in this design you will fell spinning on yourself but it will be different than in a car. But the magic of simulation is that you don't always need to stick to reality to fool your feelings ! So, if you're convinced, try it !!

I'm also working on a 3 DOF traction loss design after having built a 2DOF playseat http://www.x-sim.de/forum/viewtopic.php?t=943
I definitely will use Arduino again ! I bought everything I needed for 24V :
24V 20A 500W Regulated Switching Power Supply : 49€
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=390468751625&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
3v-36V Dual 15A H-Bridge DC Motor Driver 30A : 2x 20€
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=321143038411&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

[RacingMat]

Hello Bodgy !

Did you work out your final design ?

I could suggest something like this (to stay close to what you drawn) :
with 2 ball bearings to reduce friction when the 2 DOF's motors will shake the plateform !

[yokoyoko]

Hi Mat,
in your shown design I would suggest to use roller bearings instead of ball bearings (axle bearings). Or did I misunderstand how you want to support the "load" of the sim+driver?

Keep on discussing

[RacingMat]

what a shame !! I have been too lazy (not searching the right pictures !)

it's correct, i agree with you of course !!


What do you think about this design ?

[yokoyoko]

Or to keep the costs low - you can search a used (or new) part like this (vauxhall/vw/toyota...):
and use it as lower bearing - I would test to assemble the pivot directly to this. (your sim will not become to high - and you will not need two bearings).

The forces (during cornering) on this bearing in a real car will be higher than the sim+driver static load.

[RacingMat]

Good idea : only 34€ + 6€
http://www.ebay.fr/itm/MOYEU-DE-ROUE-ARRIERE-OPEL-VECTRA-A-1-7-TD-03-1990-11-1995-/321162577310?pt=JG_FR_Auto_Pi%C3%A8ces&hash=item4ac6c8059e
"radlager" : in french "moyeu de roue"

The advantage : compacity
Yokoyoko, what are the overall dimensions of your sim ?
The drawback : spinning (instead of sliding the rear)