cant decide which motors to use for 2DOF.

Hey Guys, this will be my first post here on the forums so please be a bit gentle with me .
Ill start out by saying my real name is Jeroen and i'm from the Netherlands meaning english isnt my native language so expect some typos here and there haha.
Also wanted to add its because of this site and its community that i decided to build my own 2dof simulator.
I had a static rig a few years back with the logitech g25 and some custom mods but after 2 years of use the rig got very old and wobbly so i trashed the parts and sold the frame.
Now a few years later i want to build another one, but this time with proper gear and
motion.
Well, after one week of reading here on the site i decided to build it so now i'm in the proces of designing and searching for parts.
What i learned already is that i will need JRK boards to drive the motors and use Server PSU's to power them, so far so good.
then the next step would be the motors, i know i could use wipers but i dont want to go that route, i would like te use some beefyer motors so i checked every link to motors that were given on the site and ive must of read the advices 3 or 4 times but still i cannot decide which one i should go for.
Some projects on this site use motors (12V 150/160 RPM and 20 NM 25:1 ratio) from ebay, at first i planned on getting two of these but then i saw the same motors but with a 50:1 ratio so thats about 80 RPM with 40 to 50 NM.
I know its all depends on what kind of rig i'm gonna build but that is also still undecided. i'm leaning toward a frame so the pedals and wheel move with it but after reading some advice here on the forum that a seatmover will deliver more realistic movements i cant decide which route to take.
Maybe someone is willing to give there 2 cents what they think is nicer to drive, or what feels more realistic to them.
If i should go with a full frame wouldnt it be better to choose the more powerfull motors? even though they are slower they are still 80 rpm so thats more then one revolution every second, isnt that fast enough for a motion sim?
Im definitly going for shoulder mounted rear motors so could you guys give me some advice which motor and which type of sim i should go for?
Any help/tips/advice would be much appreciated as im still a big noob in the motion buisness haha.

Thnxs

motor 1 : http://www.ebay.com/itm/GEAR-MOTOR-...384?pt=LH_DefaultDomain_0&hash=item51bd392f00
motor 2 : http://www.ebay.com/itm/GEAR-MOTOR-12-VOLT-GREAT-FOR-SAWMILL-CRAB-POT-PULL-FEED-75-80RPM-50-1/351093944483?_trksid=p2047675.c100010.m2109&_trkparms=aid=555012&algo=PW.MBE&ao=1&asc=23769&meid=7847818039416177308&pid=100010&prg=10163&rk=4&rkt=24&sd=351066992384

All depends on end weight of frame, and design, Seat Mover which represents (my opinion) more of the feel of whats actually going on in the cabin, but not real good for flight the 25:1 are what you want and will deliver harsh , sharp movements.
But if you want the whole rig to move which doesn't emulate properly whats going on, I find it to be very arcade like, use the 50:1 (60:1) to gain a lot more torque to move the extra weight.

If a dedicated racer I would build a seat mover with 25:1.



Motion recorded from a solidly mounted camera off the back of the chair and has a 120kg driver in the seat too, noticeable rattle you can here is the sudden changes of direction, matching the speeds of a scn5, and yes JRK 25:1 motors feed by 600ccAmp DC Battery.

Exactly the type of advice i was looking for and after seeing the video i'm already convinced on the route i'm going to take, a seatmover it is, also when thinking about it, it makes sense you got to "hold on" to the steering wheel and pedals cause of the G-forces that would be involded in real life.
The motors do seem very fast indeed in the vid and also seem to pack a good punch so i will be ordering two of those, thank you.
Also i would like to know opinions about adding the traction loss or driftframe effect, is it a must have for racing games?. i'm thinking about adding this feature as its not that hard to build and i still need to order everything so its cheaper to get them now then later on with shippin costs and all.
Maybe i wil build the seatmover first and then expand it later on, aahhh idea's idea's idea's.
thanks again for the advice so far, and ill try to keep the build thread updated and post pics when i start the build.

Im in the middle of a traction loss addon for my rig, basically the whole seat mover and static rig will sit on top of the traction loss frame, simple and independent from the Seat Mover, gives the option to shut it down and not effect my rig.
But yes very handy for simulation if you can feel the rear end loose grip a must for a serious racer.

Hi Jeroen and welcome! When using adequate motor power on properly tuned rigs, my opinion and perspective is that a seat mover more accurately recreates the trashing about your body would be doing inside a vehicle due to g forces while a platform mover more accurately recreates the feeling of weight transfer of the vehicle due to g forces! There are pluses and minuses to both systems! A couple of them are that seat movers (that I’ve seen) can’t accurately represent ‘heave” imho because they are incapable of moving your entire body (especially legs and feet) in a direct upward and downward manor and for a long enough duration. But since platforms movers usually must contend with a lot more weight to move around that makes it more difficult for them to reproduce the faster direction changes that a seat mover can. But both systems can give you what is important, that is a “feedback” mechanism that allows you to “feel” what is happening so you can make adjustments to your diving based on motion cues instead of only visual cues. When first testing my rig and before proper tuning was completed, my motion cues were off. I was not able to keep the car on the road even while maintaining the proper video cues. Once I got it tuned in though, I can now tear up the road much more easily than just using only video cueing!

I just finished building a second platform mover with only racing in mind (first one built with emphasis on flight). Now that I have it dialed in, it will rattle your teeth on those bumpy sections of road using heave (btw I love driving Hidden Valley Raceway but for a permanent course, the long straightway in front of the pit area will rattle your teeth, jaw, bones, balls, … well you get the picture). And I have to say that you haven’t experienced the “Dirt” series until you have done it on a rig with adequate heave! As you come off the jumps, you can feel the car become “weightless”. Of course, the opposite is true when you hit the ground again and feel the compression. Also, I must say that with my platform mover, a traction loss feedback mechanism is not necessary. When a car starts loosing its grip on the road, it can be felt in the sway feedback. The draw back though is that when sway is set to represent this way, you won’t get the right/left trashing that you get out of a seat mover. But for me personally, that’s not the kind of experience I’m looking for. However, I do move the seat that’s on my platform but only in 1dof, surge. This greatly helps with the “feel” of acceleration and braking. My second rig doesn’t move monitors with it so surging the platform itself much isn’t possible.

So the bottom line is both systems are good! It just depends on your preference and what you wish to experience! But, to go the platform mover route, plan on at least 2 or 3 times the budget needed for a seat mover and a lot more time to implement it!

Heave is interesting on a 2DOF balanced as I find in a car, the front wheels hit a bump first , then the back, so the front lifting to create heave (bumps) works for me. After a while, I tend to forget I am in a 2DOF and just get lost in game and motion, even pitch over jumps and coming down to crash, you tend to squirm a bit.
With drift, in a dirt game with the car getting sideways, I tend to shift my body in the seat to try to counteract the yaw I am not actually feeling, but I think I am .

Probably irrelevant information, but heres a review I did on 2 of my sims in the past

Heres what I came up with, didnt record lap times. No frame made made me faster or slower, so times were about the same.

Comparisons between simulators. Other people will of course differ with this comparison, so please add your thoughts.

First things to consider, angle of actual swing of the frames and the profile written. Also, its a brain trick.
If you want a big swinging frame, go hard, the biggest swing I have had is 14 deg total, but others have frames up to 25 deg. And thats for race, not just flight.
Both frames use same motors and JRK control boards

Seat mover with shoulder mounted motors.
Generally ,a seat mover can give more precise motion detail as it has less over all weight to move than a full frame. However, too much movement can make it hard to hang onto the wheel or mash the juice pedal. And yes, the wheel and pedals are stationary, so proper placement to allow you being pulled away and pushed around has to be taken into consideration. But as said, it does give you the feeling of being moved around in a seat in a vehicle, even with a race seat to hold you in more. You tend to shift your body around to compensate for movement and also what your brain thinks you are moving like. You can still feel pitch and roll of track, but maybe a bit less as legs are still.
Some SCN seat movers on videos have HEAPS of throw. It might look like fun, but can be too much and eventually make it tiring to drive the game.
As mine is DIY and has 70mm travel of motor lever and at 600mm from the pivot , total angle is 6.5 degrees. Not much, but then again, too much may make it too hard. Other people will of course differ with this comparison.
I had a seat mover of 12.5 degrees at one stage, so with a good profile, it was nice, but a harsh profile and WHOA! Fun but hard to hang on.

Full frame with motors mounted near feet
Full frames allow you , wheel and pedals to move with you. You dont really get sensation of being pulled, pushed around from pedals and wheels. Obviously not as much as a seat mover, but still there. You tend to feel a bit more of the motion of roll and pitch , when your whole body is getting moved around, I find.
Seat mover can lose this a bit, but not really much.
Motors mounted at feet on the frame in question, may take away some of the finer vibration and motion that shoulder mount gives, but then again, shoulder mounting motors would return that finer detail due to higher leveage point. It may lessen a bit due to the fact that a full frame requires a bit more power to move. But hey, just change the profile and increase the motor power a bit more.
Although, I must say, once again, a good profile can give the same sensation in motion, be it from a different spot. Feet or knees instead of shoulders.
Full frame is about 8 deg total swing. May not sound like much considering 4 deg from centre, but again, throw a decent profile in it and you feel like you are moving a lot more.

Summary
After a while I get the same sort of feeling from both my frames, even though they are different in design.
In your choice of motion sim build, It will come down to watching videos of other frames, opportunity to play on sims when they are around to do so. Taking a look at pics, seeing what takes your fancy. Heck, even a seat mover can be converted to full frame later, add the extra bit, move pivot, and off you go. 2 seat movers I have sold, the owners have since converted them to full frames, their choice of course. They enjoy both frames they tell me.
I have only played on a $40,000 VRX dbox with 3 screens, impressive rig, but motion was lousy I though. Although others whom have such rigs wind it up and get great results. Mind you, I dont have that sort of money to get one.
I have played on SCN seat movers, Simx kits and mine do the same for a lot cheaper.
I have been through 10 different 2DOF designs, starting with joyrider design with about 9-10 deg total swing with screen on it. Good fun, but I found it a bit difficult to focus ona screen moving with you. But thats just me.
Then I moved onto development of more compact designs, with motors under rear, at knees, out the side, shoulder mount, at feet. Still 2DOF. Screen static.
So thats how I go here. Each frame design is a new learn to drive experience I find. Nothing makes me go faster I think. I am slow regardless.
I may have missed something and please add your thoughts as well. Its always good to compare notes.

Just to "spam" it a bit more,
videos of DC seat mover, shoulder mount

Desk racer

Desk racer on board camera (mobile phone gaffa taped to the side)

Big worm gear 12v 200 watt 25:1 boxes and JRKS on all of them

My bad! I should have read more carefully! You possibly want to do 2dof on a moving frame, not a 3dof platform that I described. Sorry. For that I too would just move the seat only for the reasons stated above. If you get the “bug” for building as some of us have here, you can make changes in the future if you wish to.

@BlazinH, no pictures or videos ?

After reading al those VERY well explained opionions from everybody i have decided why not build both?. basically i'm just gonna build a seatmover with the option to hard mount the pedal assembly onto it and not the wheel. to countermeasure the change in weight distribution i will either set the seat or the u-joint on a rail of some sort with only 2 positions, maybe even with a proximity sensor to sense if the pin is in the correct slot to protect the motors and jrks, (and maybe just because i can haha)
I'm a metal fabricator / welder and can build almost anything and im planning to build this thing as i go, this method always works for me so for now i cannot really tell how its all going to work out but ill figure it out when i get there.
Got a friend who always buys and sells through ebay so i get him to order the motors for me, and i found the jrks in europe for 80 euro so i will be ordering two of them this week. the motors could take 8 to 10 weeks to arrive but thats ok, dont have anything build yet and i dont even have any gear yet like wheel, pedals etc etc, im planning on buying the Fanatec clubsport base with the gt2 rim, V2 pedals and shifter, that thing looks absolutly beautiful .
Anyways, im going to continue the hunt for parts and will be ordering the tubing for the frame next week, cant wait to start building it haha.
ah almost forgot to ask, im curious about the angels of the arms and the positions of the motors, i did read some topics about that here allready but im still not 100% sure. i was thinking to place the motors 350/400 mm outwards from the center of the seat and all the way back untill i reach arround a 60 degrees angle on the tierods, the mounts behind the seat spaced about 500 mm should do the job fine i would think.
Thank again guys for all that info, very nice read and it helped me alot.

got a sketch of your planned build?

no not really, its all in my head haha, and to be honest if i would attempt to make a sketch it would look like any other similar 2dof system.
A big rectangular base or bottem frame to support the motors the seat and the u-joint mechanism and also to give it the needed stability, so for now the only thing i need to know is where i should place the crossmembers to support the seat in relation to the back of the bottem frame, or in other words how much frame is needed behind the center of the seat to support the motors, really would like to make it as compact as possible so the less frame sticking out the better
If its not all that important to place the motors lats say within a cm for it to work properly im just gonna sit there and lay the frame out around me and tackweld it in place .
I'm guessing i could start a new thread in the project area soon cause the first bits and bobs are orderded and on their way as we speak.
Still trying to find myself a nice seat, my previous rig had a nice recaro seat that was fully adjustable, sure made the long races pretty comfy haha, but that thing was very heavy, so not very ideal for a motion platform, luckily i know someone who distributes QSP parts so im pretty sure he can hook me up with a seat.
Next update from me will be in the projects area. thanks again guys

as you are building both, do you mean one seat mover and one full frame, or both together?
Kinda need to see a rough pencil and paper sketch if you can please?
a picture says a 1000 words

I'm gonna build just one seat. But with an attachment so i can hook up the pedal assembly to the seat if i want to play that way, The wheel and shifter stay static. So only the pedals and the seat will move.
Gonna try to sketch something for you guys in the weekend. Will post it here as soon as its finished.

that will be interesting to see.

Had a few hours to spare when i got home from work and made a rough sketch of the frame in paint, turned out it was pretty easy to do so this is what i'm going to build.
The view is from underneath so i could also fill in the wooden plate or board that i will mount on top of the frame.
The red area is where i'm going to mount the seat or u-joint part, there a metal plate welded on top of the frame as i'm planning to bolt the u-joint to the frame with a 4 bolt pattern flange.
The blue area is where the motors are going to be spending their time for the rest of their lives .
Maybe the motors will also have metal plates welded underneath them to support them but i dont even have them yet so im not going to worry about it.

looks good so far, similar to how I built the base for a sim I did

I see you have the seat placed more towards the front of the frame, didnt know how much space was needed behind the seat but your picture says it all, will change the seat position bij about 20 cm so the motors can be placed further back.

never judge a frame by the person building it.
Pivot is at best balance point
Heres a clearer shot
actuators sit back about 15 ish degree

same with former DC motor sim

Normally the pedals and Wheel/shifter stay still, or they all move. If you move just your feet/pedals and the Wheel is static you may get sore knees when they are driven up into the static frame holding the wheel.