2+2+1 DOF

[mimicXtreme]

to make a long story short ...
drove race games for several years (examples: Viper Racing, Grand Prix Legends, Live for Speed etc.)
always with my "Logitech WingMan Formula Force" wheel from 1999 - which covered dust for a decade then
drove Kart for the last several years - received a hint to a "Race07"-community ... and got addicted again!

will finally get a "Fanatec Forza Motorsport CSR wheel value pack XL" very soon
THEN I'm going to build MY race simulator (in-mind-construction in progress for some months now) ...

for more details see below:

1st step: RESEARCH
comparison of the different "builds" and check pro and con

6DOF/8DOF or 3DOF (like www.force-dynamics.com)
pro: realistic
con: expensive, complicated programming, high power consume, loud

2DOF
pro:
- small, light, easy to do, only few cheap parts necessary
- good feel for curbs, bumps, motor rev etc.
con:
- poor feel for braking, accelarating, cornering, no skidding
- wheel and pedals are NOT moving with the seat -> absolute "no go" for me

2DOF "joyrider"
pro:
- light, easy to do, cheap parts
- good feel for braking, accelarating, cornering
- everything (seat, wheel, pedals, monitor) moves together -> "in car" feeling, I presume
con:
- poor feel for curbs, bumps, motor rev etc., no skidding
- slightly instable construction -> the hole structur is swinging when fastly moving

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"Force Dynamics 401" -> www.force-dynamics.com
a pro solution used for training "real" race drivers. But in my opinion somewhat "overdone", besides for the prize of *gulp* over 50k in US dollars.
And after one hour of excessive speeding your brain got shaken out of your skull!
Could even buy me a real race car for that money. And a real good one ...
Besides to the perfect simulation of all g-forces coming up in a race car, I noticed that the actuators have to carry the whole weight of the equipment AND the driver.
A lot of stuff to push around. Not only that heavy gearing is needed, it even wastes a lot of energy.

So what the hell can I do? Better? Damn ...
Build something that at least can simulate most of the stuff the 401 can, but with less material, energy waste and (most important point) do not have to sell my house to buy all the material I need.
Some people are mentioning springs or dampers for "catching" platform movements and therefor save energy and money by using smaller motors.
My theory is to put all those ideas into one simulator.

So we have 3 axis to move plus the "pushing & shaking" of 2 separate actuators. The structur should be build of aluminum rails and all should be balanced out so the electric motors will not have something heavy to do as to "break and turn around". Want to use the suspension from Pocket Dirt Bikes for that.
2 small motors per axis (that makes 4), and 1 for the rotatable foundation (on Inline-Skater-Wheels) to simulate the skidding (which does not have to move real fast like the others) can be used.
Advantages: no high level programming like the 6- or 8-DOFs, low price material - especially the motors, every "level" in the simulator can be adjusted seperately, low energy input because the weight is "balanced" through the suspension.

AND to be true ... I didn't have a chance to try ANY race simulator yet - no matter if private or commercial built *sigh*
in the end this is one of my main problems -> ending with a well functioning, but unpleasent simulator in my garage
the only thing I ever "entered" was a hexapod driven space simulator in an amusement park ;o]

[motiondave]

Hello, I may be able to enlighten here from one persons opinion.
Not matter how bad the frame or how good the frame, once you get a good motion profile, it works and works well.
I have had a joyrider, seat mover and frex. All were good. Personal for me is frex with wheel and pedals moving with you and screen static.
Joyrider was good with wipers, but I didnt really advance further due to the size of the thing.
I have built 3 seat movers, and with not too harsh movement and good bumps, it was a great ride, all of them.
I have also built 4 styles of frex, with wipers and big worm gears. once again, great rides once the profile is sorted.
A 2DOf may be only that, but I can tell you from experience, there may be no "drift" in the frame, but your mind "thinks" your are drifting and usually you try to shift your body to compensate. I know I do.
Sure braking and acceleration is just back and forth, but once again, your mind thinks otherwise and your body tends to react to this.
I have an 84 year old buddy with a seat mover and he agrees that profile making is the key here, and his ride is a basic wiper motor seat mover.
Sure it would be nice to have a"yaw" swinging frame in the rear and if you have the room, the money to engineer, go for it.
As said, any simulator you build, once you get profiles sorted, that so called "unpleasant simulator" will rock your world.
Cheers, David.

[mimicXtreme]

Thank you very much, Dave!
Your reply made me feel much more "comfortable" with my ideas.
To make it a little bit easier to follow my visions, here some construction:
http://www.die-rohlfings.de/simulator-frame-from-side.jpg
http://www.die-rohlfings.de/simulator-frame-from-top.jpg

[motiondave]

Sorry, I am too simple, can you please write on the drawing what is what?

[mimicXtreme]

your right - should have give it a bit more time
plz be patient ...

[motiondave]

ummm... I am being patient...