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2 DOF with Traction Loss, harness tensioner and more to come

Discussion in 'DIY Motion Simulator Projects' started by My.stAr, Nov 29, 2016.

  1. My.stAr

    My.stAr Member

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    Hey guys,
    i registered i while ago but didn't really had specific plans to build my own motion rig. But now the time has come where i have lots of time:grin

    I read a lot the last days so i have a clearer picture of what i'm going to build. I'd like to use linear actuators. I already have the ball screws. 6 of them with the same length. And some which are longer.
    ball screw open.jpg ball screw closed.jpg
    The pitch is 5 mm. They can move a little over 300 mm. In the end, they will look different from the actuators of SeatTime, SilentChill or wannabearflyer2. I'm planning to use the moving part and extend it to the rig. The ball screws also have build in end switches, hopefully i can use them:)
    I also have matching 5 phases stepper motors. But i don't plan to use them.

    First i want to build a rig like SeatTime/wannabearflyer2. But for the beginning as a 2DOF. The front will be "fixed" and in the back there will be 2 actuators, a typical seat mover. I want first go a small step to get used to everything. And if everything is fine, i can add 4 more actuators and enjoy a 6DOF motion sim.
    So are the plans...
    After reading some very very long topics i know, how much problems there can be.
    So i also decided NOT to use MMs;)
    I'm still not sure about the motor, probably 24VDC?!
    I have to make a lot of decisions...

    And i'm really happy, that i can find here lots of answers to my endless questions:thumbs
    • Like Like x 3
  2. obobo

    obobo Active Member

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    interesting project
  3. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator SimTools 2.0 Beta Tester

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    My Motion Simulator:
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    Starting with a 2dof does lets you gain valuable experience.

    Where you are in the world, cost and availability can all be factors affecting motor choice.
  4. My.stAr

    My.stAr Member

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    @noorbeast i read this several times, that there are lots of problems with getting the right stuff in the wrong country;)
    Since i'm from Germany, i think it shouldn't be such a problem. It's just a matter of choice. At first i wanted to take stepper motors, then i switched to servos, ... and depending on this decision the other stuff will also vary. I still have a lot to read and search.
    When i have the right motors i can also buy the other parts.
    But i will start with constructing the rig... and then going to make some actuators.

    @obobo thx
  5. My.stAr

    My.stAr Member

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    I opened another ball screw and there was a nasty surprise:(
    Another Ball screw another structure. It has a thread pitch of 10 mm and also different end switches. Spindel.jpg

    So it won't be possible to build 6 identical actuators for a 6 dof sim. But i'll find at least 2 of them and can make my 2 dof sim.

    The advantage with 10 mm pitch is the faster speed;) I'll just need stronger motors...
  6. My.stAr

    My.stAr Member

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    So, here is the first design of the possible frame. dimensions are not final. i still didn't decide whether i'll take 40*80 mm for the frame, or just 40*40. It's a difference in weight by 1,3 kg/m, but it much stiffer. 2DOF.JPG 6DOF.JPG
    I think in the end everything will look different;) e.g. i won't take 40*80 for the tale in the 2DOF frame. The pictures are only to show how it will look like;)
  7. My.stAr

    My.stAr Member

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    hey, have some updates on my project.

    first of all i hope i found my motors:D
    It's a Lenze 24 vdc with 370W. They are old, but unused and i can have them for a fair price. They are strong enough for 10 mm pitch ball screws... i hope;)

    Since the motors have thermo switches, i'd also like to use them. Am I right, if I asume i can implement them with Arduino?

    Another question I have is the choice of the right motor controller. If i take the Sabertooth, will the 2x32 version be enough? With the 370W motors the current should be about 15A. BUT the motors are rated with Imax=90 A !!! So more than 2 kW:eek:. So my question is, will the motors really need so much current? 6DoF, 10 mm ball screws and i'd like to stay without struts...
    I'm asking, because i want to save the money and not buy the expensive 2x60 sabertooths.

    Attached Files:

    Last edited: Oct 10, 2017
  8. adgun

    adgun Member

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    I dont think a 370 watt motor can handle a 10 mm pitch, but is it possible to reduce the screw 2 times with a belt!
  9. My.stAr

    My.stAr Member

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    no belt, i want it directly attached:cool:

    Why should it be too week? @SilentChill and @wannabeaflyer2 have the Parvalux with 270W@4000 rpm --> 0,64 Nm @ max rpm.
    The Lenze has 370W@3000 rpm --> 1,17 Nm. almost the double torque for the double pitch. And I assume that with a maximum current of 90A it should have enough. I know it's just a peak current.
  10. My.stAr

    My.stAr Member

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    If my calculations aren't wrong i have a force of 730 N with a torque of 1,17 and a pitch of 10mm. so one actuator should be able to lift me with full speed @ 500mm/s. Ok ok, in reality there is friction. so maybe me without my legs and with just one arm.


    Edit:
    sadly the man with the motors made a mistake. The rest of them are worm gear motors. So if someone is interested in them, i can give his e-mail address;)

    I have to look for some new toys:/
    Last edited: Dec 28, 2016
  11. Pit

    Pit - - - - - - - - - - - - - - - - Staff Member Moderator Gold Contributor SimTools 2.0 Beta Tester

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    My Motion Simulator:
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    Where are you located? Basically I'm interested. PS: du kommst aus DE, bitte sende mir eine PM. Danke.
    • Friendly Friendly x 1
  12. Blame73

    Blame73 Yet it moves!

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    Are they all 24v?
  13. OZHEAT

    OZHEAT Member

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    l don't think the 370w motor is under powered, too much if anything.
    You do know that 300mm travel is 30 turns only, not much to play with when a rated speed@3000rpm equals 50 rev per second.

    With the worm drive motors, why not buy them and remove the gearbox?
  14. My.stAr

    My.stAr Member

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    Yes, afaik all 24V with 370W.

    I also have some 400mm actuators. And both lengths also with 5 mm pitch. For the 2DoF sim this should be enough to play with. And if i'm ready to build the REAL thing i will buy some longer actuators, if needed, but i think it will be needed:D

    I don't know what shafts the motors have. I asked him, and am still waiting for an answer.
    Maybe i will go that route. I mean, this are industrial motors. No chinese toys;)
    Last edited: Dec 29, 2016
  15. My.stAr

    My.stAr Member

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    hey,
    i have to revive this thread, because i finally made some progress :D
    It took a while to find the money and time between all the problems of life, but now i have almost everything together what i need for my first rig. And i also have some more pics now ^.^
    pic 1: I have lots of aluminum extrusions to chose from
    pic 2: at the moment i plan just to fix the sled of the actuator directly to the extrustions. In the 2DOF version it's no problem.
    pic 3: this is, how it should look like in the end. it will be a frame-mover, not a seat mover. i love this sparco seat *.*
    pic 4: lots of kangaroos (--> bought a used set of kangaroos, pots, arduinos and sabertooths...)
    pic 5: pots
    pic 6: 2 arduino boards. I also bought 2 of them before, so i now have 4 of them :D
    pic 7: sabertooths 2x32. I have some more of them, but they are broken, i don't know, if i can fix them...
    what you cannot see on the pics are the motors, i have 250W 12V Motors. got them quite cheep. sooner or later i will go for 24v motors

    Now i have a big thing to decide:
    Where to put the pivot point?! The further i put it to the front, the more heave i get with the actuators in the back.
    An idea i recently had was: can't i put the pivot point completly to the front and then also use the 2 actuators for traction loss (pic 8)?! i know, that 250W motors won't handle it with a ball screw pitch of 5 mm, but what if i take stronger motors? would it work or do i miss something?


    Since i have now more than one sabertooth, and also several linear actuators i can add some axes quickly. hopefully i will get some 24v motors soon (they are about to be shipped). Then i can build a belt tenstioner, a g-seat. And after that i think i will go to the 6 DoF-rig. That's the plan for the moment. But i have lots of other designs in my mind...
    First the 2dof rig, then i can add a traction loss and other axes quickly :D

    Attached Files:

  16. My.stAr

    My.stAr Member

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    So, next steps are done. I did construct a provisional test station for my actuators. I can add weight and evaluate the possible actual force of the actuators. And according to the results i will put the pivot point somewhere, the motors can handle the weight (I'd like to have it as far to the front as possible). Yesterday i brought a car battery home, maybe i can make some tests this weekend:D
    [​IMG]

    Today some 24V went on their way to me:D
    one 400 W: i'm planning to use it for traction loss. and 3x 250W Motors with wormgears: If my 12V Motors are strong enough, i can use the 24v Motors for a g-seat and belt tensioner. If the 12 V motors are to weak, i will have to swap them with the 24v (use them without wormgears) and add some gearboxes to the 12V motors for the g-seat.

    The G-Seat will be built in the first step with Wood. It will be with bowden cables, i also already have them (handbrake cables from the same car, i have the battery from and maybe i will use some more parts of it :D ). If it works fine, i have to find a solution for my sparco seat... maybe i will cut it apart:rolleyes:
    Also the belt tenstioner will work with a bowden cable:) So that's why a want the motors to have a gearbox, they can stand on the floor and i don't add much weight to the rig:thumbs

    And if i count the axes together i will already have 6 of them, without having a steward platform :D
    Maybe in some years i will have something like @SeatTime with 12 DoFs :grin

    Attached Files:

    • Like Like x 3
    Last edited: Oct 30, 2017
  17. My.stAr

    My.stAr Member

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    Next Update (I know, it's going really slow, but i have lots of other projects :cool:)
    I made some extensive tests with the car battery and my test station. The result was, that the battery is dead:mad: it was charged the day before and was empty when i needed it:/ no luck. now i have some power supplys, i hope i will be able to make some test this or the next week.
    PSU.png
    Yesterday i cut the aluminum extrusions and built the upper frame. Nothing special so far.
    IMG-20171030-WA0003.jpg IMG-20171030-WA0004.jpg

    The upper framewill be fixed with a u-Joint and the actuatros to the middle frame. At the Moment the u-joint fixing point is moveable back and forth. The Wheel part will be adjustable in height and the angle. Still have to decide how to attach the pedals. And also the wheel. The easiest thing would be just to drill some holes through the extrusion and hard mount the wheel...
    IMG-20171030-WA0002.jpg (the Picture was made before i cut and drilled everything)


    The middle frame is from steal, i have something laying around i hope i can use it. Between the middle and the bottom platform will be the stuff for traction loss. Didn't decide yet, how it will be done...
    hope next updates will come quicker :think
  18. My.stAr

    My.stAr Member

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    This are the two reasons, why i cannot work on my simulator :(
    IMG-20171101-WA0011.jpg
    It takes its time to totally detach the car... BUT i can use some parts of the car, and i get money for selling them which can be used for the Simulator:cool: --> already have the money for a new SSD. hopefully i will soon get enough for a new grafics card and also VR glasses (pimax 8k?:rolleyes:)

    IMG-20171103-WA0009.jpg
    This also consumes a lot of time... BUT it's the room, where the simulator will bring me lots of joy:D


    So, at the moment i have no progress with the rig, except of ideas:
    - i'd like to use my T3PA Pro pedals partly inverted:rolleyes: have an idea how i can manage it,
    - it becomes clearer to me how i will build the lowest platform
    - thanks to @SixDegreesOfFlight videos it becomes easier for me to get used to the electronical stuff... still didn't start to tinker with it, but i soon will:blush
    • Like Like x 1
    Last edited: Nov 4, 2017
  19. Seth2Christ

    Seth2Christ Member

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    Personally, for now I remain cautious about pimax 8k ...
  20. My.stAr

    My.stAr Member

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    @Seth2Christ can you tell me why?

    I recently bought a 980Ti. This card will definetly be too weak for a pimax 8k. and i won’t have the money to upgrade soon… I almost got an oculus CV1 for 200€ with controllers and everything. I called the guy 10 minutes too late, he sold it to the faster guy
    no news with the rig itself. i’m upgrading my computer atm, with the water cooling systems it takes longer than i thought.
    Next week or the week after i will get my other motors (24V, 250W and 400W) and the PSUs. So then everything will be finally together :D and i can also show some relevant updates (i think no one is interested in my disassembled computer...)
    Last edited: Jan 19, 2018