My first go to build a 2DOF

Hey Guys, some of you may have seen me ask a question here and there but the time has come to really start ordering things and to start building.
I'm pretty new to the concept, 2 weeks ago i didnt know anything about motion sims and stumbled upon the idea of adding motion to the new sim i was planning to build so i googled and found this site, after reading for hours and hours it all started to make sense and figured this isnt even so hard to build so i thought about for a few days and now i allready got the jrk's and motors orderded
I also orderded the tubing for the frame and its all gonna be made from 30x30x2 mm square tube.
Theres not really going to be upper frame as the wheel and shifter will stay static and will be mounted somewhere to te bottem frame, the pedals can either be placed static on the bottomframe or attached to the seat so they move with it, this will be nothing more the 2 square tubes sliding in one another or by hanging it under the seat and putting a pin in place, dont know yet, we'll see about that when its time to fabricate that peace.
Also thought of making or buying a large enclosure that will hold all the electrics like jrks , psu's, amps, relais and the main switches, so this will be one of the first things i'm going to build as it going to be the heart of this thing haha.
Made a design for the frame in Paint this afternoon and came up with this, not 100% on all the measurements of the frame but there not that important so the frame is not to scale or anything, just freehanded all that .
Have some other project going next to this so i wont be going at it on a daily basis but there will be frequent updates.

Grtz

looks good man

Going to continue here as the old post was about the motors and was allready answered

there are just to many variables i think to predict what is going to happen so i'm not going to bother right now, i will build both the lower frame and the seatframe and mount the seat and just play with the positions of the motors and the mountings on the frame to get the desired feel and motion.
Which leads me to another question about the Pots on the motors, would it be any better to have a motor to Pot ratio of lets say 2:1 or even 3:1 to get a better resolution ?.
I figured cause my motors are 50:1 theres a good change i will be using LESS travel on the motors compared to a 25:1 if i'm going to play arround with the configuration of the motors and such.. not saying this will be the case but even with full throw on the motors your only using what? 70/80 degrees? so adding a ratio of 2:1 would give the pot 160 degrees to work with, therefore adding more resolution for the JRK to work with. i would think the more you could utilize the pot the better it would be, yes/no?
Thanks

Id better ask another member about this , @eaorobbie , as you use a shorter feedback setting, but I recall Rob uses a single turn pot on the back of the motor shaft directly though.

So today i got some work done, the square tubing got deliverded yesteday so i started building the bottem frame, the plans have again changed a bit and i will be building a frame that moves the seat, pedals and the wheel, i didnt picked those 50 NM motors for nothing haha.
The frame sits on 5 rubber mounts to reduce any vibrations and noises so the misses downstairs doesnt have to wear headphones when watching tv , drilled a large hole in the plate that will hold the u-joint and i'm planning to lead all the cables through a vacuum cleaner hose so it doesnt look so messy and i also fitted some brackets underneath the frame that wil hold the cables so they all exit in one spot.
Finished it off by spraying some prime on the thing so it looks more "done" haha.
In the end its going to have a wooden or aluminium plate on top to close the frame off.
Also got the JRK's and pots deliverded and i decided to have the pots on a 3:1 ratio so a wider range is available for the JRK to work with so after i finished the frame i also started on the bearing housing for the small poulie side, the side where i wil be connecting the pot to. the parts are made on a lathe except for the bearings offcourse, still had these laying arround from back in the day when i was into 1:5 scale Rc racing, I didnt made the larger poulies yet because im going to make the locknut for the lever arm and this poulie out of one piece and i have no clue yet how these motors look and what the connection for the lever arm look like so im not going to bother right now.
Since i work in a hydraulics company we litteraly have tens of thousends of o-rings i thought of using o-rings for the linkage between the poulies, and since we have so many sizes its pretty easy to set up, i just fit everything where i can and pick an o-ring that suits.
Anyways, here's some pics of todays work:

Nice, clean project.
"Thought I was a good welder" - but this is some of the best welding I've seen in a long time.

Blessings,
Tom

its coming along well

Thanks Tom, ive been welding for about 12 years now, started as a hobby but now its a full time job, really love working with steel and i'm always busy making stuff and thinking of new projects i can build.

last week i made a custom manifold for a old rally car and im also working on a sprint scooter build which i build from scratch. yeah, i'm a busy guy haha.

jerome16v,
Just beautiful work. I love to see a craftsman at work. Very impressive my friend.

Have a blessed day.

Tom

well it has been over a year but i finally have some time to work on this project again, did most of the work allready and have been using this rig for the last few months now, motionless that is. The Fanatec gear arrived in november 2014 and was laying arround my house for a few months before i welded up the base and installed everything to it so i could atleast play some games with the new toys.
The main reason this project got delayed so long was because in the beginning i wanted to convert one of my spare bedrooms to a game room where this rig was going to be placed but after buying the beamer and all the parts i needed i realised those rooms were way to small so that wasnt an option anymore.
So the first logical thing i could think of was converting a part of my garage to a home theater so i did just that.
Took me a few months but its 90% complete now and it turned out really nice, 2 amps, 6.1 surround, 3 active subs and offcourse a black and dark red finish to make it feel like your actually inside a movie theater .
After all this was finished and working i could begin installing al the parts for the motion part of the build into the theatre and that about where i am right now.
Got everything hooked up, and im in the middle of testing the JRK's and motors, all went well in the beginning but ive ran into some issue's.
Ive allready described the issue's on the Polulu forums and i will add the link or just copy paste everything here so i dont have to type it all over again.
Meanwhile i will just continue welding up the motors to the rig and finishing the build as the problems im having right now will be fixed eventually and dont have anything to do with how im going to build this thing.

This is the topic where i explain my issue in detail, its a long post and has pics so i didnt want to spam this thread here
http://forum.pololu.com/viewtopic.php?f=15&t=10353

the photos on the bottem are from the build, and from the first "test drive" but ill add some more recent pictures soon


Heres a video of me trying out the mclaren P1 on the nordschleife and a video of testing out the parts i made to drive the potentiometer and a quick look of all the components

Beautiful! Nice work! I wish I would be as talented as you with steel!

Interesting build, One question tho. How tight are those Oring's for the Pot's ? I would almost fear a little Slipping situation in fast direction changes......then again if they are rather snug it might not be an issue at all. Are you planning on running some Flex Couplers ? 6.35 to 6.35 ?

@jerome16v , ive read the forum posting.
Are your pots centered on the feedback
I am guessing you may not have centered the pot feedback right.
Heres a suggestion
"
Setting feedback, with the pot connected with its shaft to the gearbox, I opened the utility program, went to feedback tab, click "reset to full range" , clicked apply, the I unscrewed the nut holding the shaft and using a permanent marker texta, I rotated the pot body around and I looked in the graph, (top right hand corner) , in fact I double clicked it to make it bigger. I turned the pot till it started to show a reading of the line. Once I found the 50% mark, I put a mark of texta on the motor housing and a mark on the pot body so I knew where the centre was, from that point I turned it slowly one way till I found the near 80% mark, put a texta line, then turned it the other way till I found the 20% mark in the graph, marked it again with a texta. Then I moved the pot back to the centre to match the centre position of the lever.
"
Heres a short guide to setting motor power and PID
"
Guide to setting PID and motor settings on JRKS

max accell and max duty at 500, max duty while feedback out of range 500

current calibration 130

max current 0 (unlimited)

PID period 20ms

Integral limit 10000

With PID, Leave I alone and at 0

Using the slider bar in INPUT tab of utility only, no simtools, this is how its done.

Set P, I , D to 0 in the decimals, apply settings, now start with P only and work up in increments of 0.1 , apply settings, go to INPUT tab, tick the box "automatically set target", click run motor and either slide the bar fast from side to side or use the home/end buttons to do max, min motor throwing.

Work up in 0.1, so next would be 0.2, then 0.3, etc. Until you find when you move the slider bar, the motor twitches like a bugger. Once you get that, halve that figure you have in P. So if its say 0.7 , you would put in 0.35.

Now dont worry if when you click apply settings, that the number is not exactly what you typed in.

Once the P number is halved like I said, go to D and work up in increments of 0.1 like you did with P. Apply settings, go to INPUT tab, and run motor and move the slider back and forth fast until the motor lever stops overshooting its stop point and starts to be very solid in stopping.

So for example, you may have a final figures of P 0.3672 , and D of 0.8231 for example. Do not use those figures, I am using an example of what may be the final numbers.

I have found when I do put in say 0.8, apply settings, it gives me 0.79999 or something like that.
Leave "I" at 0.
"
And yes, put a cooling fan on the JRKs, good chance they may be thermally shutting down from heat after a while of use.

Wow
I admire your ability to weld
Do you think is best this way than a couple of pinion to connect the pot?
I never saw it this way
I planned to use pinion of some old cd readers

Hey Guys, thanks for all the comments, really appreciate the positive feedback.
Speaking of feedback, I got one motor and pot connected and got it to work. still playing arround with the PID settings but the motor goes to where i want it to go, in the beginning the motor sometimes overshoot its target a bit but spend a few hours tinkering the PID settings and i think its allready amazing how fast and accurate the motor changes position. really impressive.
Still having issue's with the other JRK though, for starters the signal coming back from the pot has lots of noise. and thats with both pots and both sets of wiring, and secondly this JRK still gives me the max current exceeded error hundreds of times in a row, even with the motor leads disconnected on the board so i guess ill just order a new one, maybe i wrecked it when soldering, or maybe when testing it out for the first time, or it could have been dead out of the box, who knows.
Going to do some final testing tommorow evening and then decide what to do.

The fan is allready on, these pictures were made when i installed the wiring to the board, you can see the fan laying next to the control board in the last video, i only did some small tests without the fan but even then the JRK's didnt even get warm. had a limit of 12A en the motors were spinning freely.
The o-rings work great. i tried to hold that bolt but theres no way i could make it stop en there no play what so ever when changing direction so this will have zero issues. btw, the whole bearing assembly rotates arround one bolt and its off center so it acts like a tensioner.
I will also post some pics tommorow of the settings i have so far but these settings i have now are just for testing and getting a basic understanding what is happening when i change something so i actually know what im doing when i hook up these motors to my rig .

Ah almost forgot, the coupling between the pot and axle/bolt will be a piece of fuel line or vaccuum line in the end, for now i electrical taped the ends together haha but like i expected, this works just fine. also, the plastic pieces that hold the pots in place are very flexible, even more so because of those tywraps holding the 2 pieces together so it doesnt have to be perfect.

@jerome16v , did you get any reply yet from pololu?
EDIT, no you have not yet......
Ok, slap up pics of the JRK utility setings, might be something in there.
Dave.

nice work your simulator, very immersive installation with projector, good idea potentiometers with belt

So i made a few screenshots of the settings i have right now but i dont think its a settings issue, i just did some tests with default settings (except for changing one PID setting te get the motor to do anything and the outcome is still the same, one JRK has perfect feedback and works like a charm, not giving a single error for max current exceeded when i play arround in feedback mode.
The other JRK not so much, made a video of the feedback signals coming in from both JRK boards and from the SAME Potentiometer, you can see me switch the connector from board to board, couldnt get a shot of where you could actually see me turning the pot and see the values at the same time but i dont think you guys will doubt me if i said i am making slow 360 degree turns on the pot on both boards, the range you see on the second board is from a few full pot rotations.
The Problem with the max current exceeded didnt want to do his thing tonight, typically. but i will investigate some more.
But ive ran into another issue and this time something is definitely broken, its (offcourse) the pefectly working fine JRK that send out the smell, not the smoke but i smelled that burned electronics smell. couldnt find anything to be honest and both JRK's were still online and working so i continued to make the video and it was only when i turned off the PSU's that i saw one JRK going offline. turns out it wont power on with USB alone anymore, tried switching cables again and ports and whatever but it wont come on and it doesnt get recognized in windows either with usb power alone. it still works fine after i switch on the power suply but something definitely burned..
Dont have a clue what went wrong as i wasnt even working on this when i smelled that evil smell, the JRK's were on standy, (PC was on but didnt had the software running). so yeah, thats not really fun.
i was just getting over the fact i probably had to buy one new JRK, now maybe i have to buy 2. ah well. atleast i have my health haha.

Edit: i know the motor has to be on Coast and not Brake but these tests were after i defaulted both boards, and Yes, there is no fan, couldnt reach the connector with it on

@jerome16v , you have no feedback even set as a start , you need to set the feedback. the standard 4095. 4095, 0 , 0 is not going to help.
Its an old video, but shows how to set feedback in JRK

Also increase PID period to 20ms
Integral limit to 10000 (not 1000)
Max duty leave at 400
Max accell change to 400
Change current limit to 0 (unlimited)
drop current calibration down to 130
Then, go back to PID and start again, try a "standard" P 0.5 , I 0 , D 0.5 first and see if there is any improvement. If there is, go set PID properly

With PID, Leave I alone and at 0

Using the slider bar in INPUT tab of utility only, no simtools, this is how its done.

Set P, I , D to 0 in the decimals, apply settings, now start with P only and work up in increments of 0.1 , aplly settings, go to INPUT tab, tick the box "automatically set target", click run motor and either slide the bar fast from side to side or use the home/end buttons to do max, min motor throwing.

Work up in 0.1, so next would be 0.2, then 0.3, etc. Until you find when you move the slider bar, the motor twitches like a bugger. Once you get that, halve that figure you have in P. So if its say 0.7 , you would put in 0.35.

Now dont worry if when you click apply settings, that the number is not exactly what you typed in.

Once the P number is halved like I said, go to D and work up in increments of 0.1 like you did with P. Apply settings, go to INPUT tab, and run motor and move the slider back and forth fast until the motor lever stops overshooting its stop point and starts to be very solid in stopping.

So for example, you may have a final figures of P 0.3672 , and D of 0.8231 for example. Do not use those figures, I am using an example of what may be the final numbers.

I have found when I do put in say 0.8, apply settings, it gives me 0.79999 or something like that.