1. For downloading SimTools plugins you need a Download Package. Get it with virtual coins that you receive for forum activity or Buy Download Package - We have a zero Spam tolerance so read our forum rules first.

    Buy Now a Download Plan!
  2. Do not try to cheat our system and do not post an unnecessary amount of useless posts only to earn credits here. We have a zero spam tolerance policy and this will cause a ban of your user account. Otherwise we wish you a pleasant stay here! Read the forum rules
  3. We have a few rules which you need to read and accept before posting anything here! Following these rules will keep the forum clean and your stay pleasant. Do not follow these rules can lead to permanent exclusion from this website: Read the forum rules.
    Are you a company? Read our company rules

Time for upgrade 2DOF to 6!!

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by poman, Dec 5, 2015.

  1. insanegr

    insanegr !N$@n€

    Joined:
    Jan 14, 2014
    Messages:
    511
    Location:
    Athens
    Balance:
    16,650Coins
    Ratings:
    +496 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    have you tried [A<Axis1>] ... [A<Axis6>] one per interface as described in previous posts.you have to type the brackets too in interface output too
    EDIT:
    Set 500000 baud rate and 10bit binary output
    Untitled.png
    • Winner Winner x 3
    • Agree Agree x 1
    Last edited: May 8, 2016
  2. Pit

    Pit - - - - - - - - - - - - - - - - Gold Contributor

    Joined:
    Oct 2, 2013
    Messages:
    3,029
    Location:
    Switzerland
    Balance:
    29,900Coins
    Ratings:
    +3,045 / 30 / -0
    My Motion Simulator:
    DC motor, Arduino, 6DOF
    Interface output is wrong, please check again the SMC3 thread.
  3. BlazinH

    BlazinH Well-Known Member

    Joined:
    Oct 19, 2013
    Messages:
    2,168
    Location:
    Oklahoma City, USA
    Balance:
    16,045Coins
    Ratings:
    +1,833 / 32 / -1
    I believe insanegr has nailed down your issues. Even though I looked at it, I completely overlooked the necessity of using brackets too. :oops: And when the baud rate is set incorrectly you will either get no motion or erratic motion.
  4. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    Well, ill be dammed...IT WORKS!!!!!!!!!!!!!!!!!!!

    i am VERY sorry as i didnt thought of going back to the SMC3 page where it clearly says baud rate at 500000 and 10 bits output. The place i did thought of checking is in the SMC3.ino i could see 115200 in there so i thought i was ok
    And also, yes i forgot to mention in my video that i did tried the brackets, but since i didnt had the proper baud rate it didnt worked...wew!!! i was hoping it was only a small thing.
    TKS SO MUCH FOR HELP!!
    and btw VR is awesome, got my VIVE helmet and started playing with it, really fun!!!
    • Like Like x 3
    • Winner Winner x 2
  5. bruce stephen

    bruce stephen Hammer doesnt fix it, must be electrical

    Joined:
    Jun 7, 2015
    Messages:
    1,293
    Occupation:
    general contractor
    Location:
    michigan
    Balance:
    9,075Coins
    Ratings:
    +1,227 / 9 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform, 6DOF
    IT SHOULD READ

    [A<Axis1>]

    edit: lol should have refreshed first so glad you got it working.
    • Friendly Friendly x 1
    Last edited: May 8, 2016
  6. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    LOL, dont worry, youll see it soon with my upper frame installed as we speak, i am cutting my rods and making a couple holes for gas strut...
    • Like Like x 2
  7. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    Hi,
    Well, i am a bit dissapointed as you will see in my video, the structure is a lot more sloppy than what i expected, and i didnt showed it moving but i have an issue with the hysterisis i think(goes back and forth quickly), i know there is a couple of ways of fixing this issue with SMC3 and probably simtool, havent had time to play with that much, but as i am putting gas shock, i have been told it will help, plus the weight of everything including me. i have quite some adjustment to do i knew that, but i need to be sure the design is not to change/modify before i keep going. The changes i tought was like moving the upper ball joint on the other side of bracket, or maybe change my attachment point, or the starting position etc...tks

  8. bruce stephen

    bruce stephen Hammer doesnt fix it, must be electrical

    Joined:
    Jun 7, 2015
    Messages:
    1,293
    Occupation:
    general contractor
    Location:
    michigan
    Balance:
    9,075Coins
    Ratings:
    +1,227 / 9 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform, 6DOF
    maybe spin the motors so they face out this will give more of an angle? have you tried turning the starting points 180 degrees this will also change the angle.
  9. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    15,836
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    115,687Coins
    Ratings:
    +9,243 / 46 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    That is an awkward angle.

    Perhaps flipping the top ball joints 18o degrees and mount them om the inside of the bracket may help with the angle. If that is not viable then I suspect some significant design changes are needed.
    • Agree Agree x 2
  10. SeatTime

    SeatTime Well-Known Member

    Joined:
    Dec 27, 2013
    Messages:
    2,607
    Location:
    Newcastle Australia
    Balance:
    27,895Coins
    Ratings:
    +2,866 / 37 / -0
    My Motion Simulator:
    DC motor, AC motor, Arduino, Motion platform, 6DOF
    Hard to tell from your video but you need to check how well you are forming the right angles so that each pair of arms will support each other. A property built Stewart Platform should be self supporting and not move at all unless it is driven (its based on intersecting triangles like a bridge support). Recommend therefore you have a look at how @SilentChill has built his sim which is similar to yours.
    • Informative Informative x 1
  11. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    Hi,
    Yes, definitly the upper ball joints can and will be mounted inside the brackets because the rod doesnt clear the arm if i put the starting position 180 degree on the other side, yes i did check Silentchill a lot tks, i believe i have no choice of putting the starting poin horizontally?
    Also, should i be considering aligning the 2 triangles(base and upper frame) and attach motors accordingly? i dont think it would be right, but just asking in case...tks guys
  12. bruce stephen

    bruce stephen Hammer doesnt fix it, must be electrical

    Joined:
    Jun 7, 2015
    Messages:
    1,293
    Occupation:
    general contractor
    Location:
    michigan
    Balance:
    9,075Coins
    Ratings:
    +1,227 / 9 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform, 6DOF
    two triangles set like the star of david is the way most are configured.
  13. SeatTime

    SeatTime Well-Known Member

    Joined:
    Dec 27, 2013
    Messages:
    2,607
    Location:
    Newcastle Australia
    Balance:
    27,895Coins
    Ratings:
    +2,866 / 37 / -0
    My Motion Simulator:
    DC motor, AC motor, Arduino, Motion platform, 6DOF
    The two triangle base and upper are not aligned in a stewart Platform. Below is a old mockup of mine when I was building it - As you see it is all triangles and once it was attached to the frame later - very stable and strong. Not exactly like yours or @SilentChill , but I hope you get the idea. You are very close - it just that the angles are not quite right.

    Mockup2.jpg
    • Like Like x 1
    • Winner Winner x 1
  14. SilentChill

    SilentChill Problem Maker

    Joined:
    Jul 19, 2014
    Messages:
    2,580
    Occupation:
    Railway Maintenance
    Location:
    Morecambe, Lancashire, England
    Balance:
    19,878Coins
    Ratings:
    +3,388 / 33 / -0
    My Motion Simulator:
    DC motor, Arduino, Motion platform, 6DOF
    Flip your arms 180 degrees make much more of an angle on your connecting rods to the platform
    • Agree Agree x 1
  15. bruce stephen

    bruce stephen Hammer doesnt fix it, must be electrical

    Joined:
    Jun 7, 2015
    Messages:
    1,293
    Occupation:
    general contractor
    Location:
    michigan
    Balance:
    9,075Coins
    Ratings:
    +1,227 / 9 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform, 6DOF
    Like I said to begin with spin the arms and motors 180degrees. Also as @noorbeast suggested put your platform push rod mount on the inside. If you insist on having the motors facing inside a larger base may be needed.

    Wow @SeatTime that is one of the best examples ive seen of the triangles formed in a stewart. Ty for posting it.
  16. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    Great answers guys, will do...just need to flip ball joints inside frame to clear the arm so i can flip them 180 deg. gonna make the frame lower which is good, like in cars, wider stance is better for more stability :)
    Will keep you informed tks
  17. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    I have been hard at work, but still have issues, would like suggestions from experienced guys please :)
  18. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    15,836
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    115,687Coins
    Ratings:
    +9,243 / 46 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    I do like the overhead projector mount :thumbs

    The COG needs to be determined with the loaded weight, with all peripherals attached and with you sitting in the seat: http://www.xsimulator.net/community/faq/find-the-center-of-gravity-to-balance-a-motion-simulator.55/

    Just a design observation. Maximum effective torque is delivered at 90 degrees and falls off rapidly at an angle, and you have a significant lever to rod angle at rest. You can have a play with this online calculator to see what I mean: http://hyperphysics.phy-astr.gsu.edu/hbase/torq2.html
    • Agree Agree x 3
  19. poman

    poman Active Member

    Joined:
    Jan 5, 2012
    Messages:
    128
    Balance:
    154Coins
    Ratings:
    +95 / 0 / -0
    Tks for the projector :)
    For the resting position, that is why i am having problems to mount my chair, i have 40kg x 3 gas shock mounted on the 3 sides and i think it may have been too strong for the weight of my chair so my arms were sitting too straight and they would go on the wrong side, as it was before, and all became loose(i almost dropped it on my electronic panel), and before i put the chair on top, i had tried putting power on the rig and my motor didnt seemed to be strong enough to bring the platform to its starting position due to the shocks, i had set the Kp to 500 in SMC3, any thoughts??
  20. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    15,836
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    115,687Coins
    Ratings:
    +9,243 / 46 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Let me try and explain further about what I mean by the angle resulting in the ineffectual use of torque.

    If you look at the design for @zigzag49's 6DOF you will see the motor arm is roughly 90 degree to the rod and maximum torque is transmitted that way: http://www.xsimulator.net/community/threads/6dof-dc-24v-smolka-zigzag49.7490/

    eric_6dof_vueav_cotes-4b6a851.png

    At the moment on your sim it has a severe angle between the motor lever and rod, which will be very ineffectual in making use of the available motor torque.

    1.jpg
    • Informative Informative x 1