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2DOF Gearmotor build. (Design in process.)

Discussion in 'DIY Motion Simulator Projects' started by Mike Stuart, Feb 27, 2019.

  1. Mike Stuart

    Mike Stuart New Member

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    Ok, after enough research to make my head hurt I have decided to embark on a 3DOF build. I intend to use the PGSAW 50:1 Motors. Here is my current base design, more to follow. I intend to use my limited skills in inventor to document and make the files available once it is up and running.

    So here are the first questions:
    1) Does anyone have a model of the pgsaw motors? Or, at least a bolt pattern and rough dimensions so I can rough them in to the model? I will not be ordering until next month.
    2) Does anyone have any comments about my current base design, or see anything obviously wrong?

    Hope to delv into the electronics soon. But for now will be focusing on the actual structural build.

    Base_Rev1.PNG Drawing capture.PNG
  2. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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  3. Mike Stuart

    Mike Stuart New Member

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    Perfect thanks. I'll spend some time tomorrow modeling them up.
  4. Tim McGuire

    Tim McGuire "Forever a work in progress"

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    I checked the dimensions against my model, and I can safely say that the PGSAW and motiondynamics ones are pretty much identical
    My model is off by ~0.5mm in some places, since I was measuring by hand without a set of dimensions to work with, but it should be more than accurate for these purposes.
    • Informative Informative x 1
  5. Mike Stuart

    Mike Stuart New Member

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    Thanks so much for the model. Here is my updated model. Had some trouble mirroring you motor in inventor. Added Motors, brace rod, and bottom actuator rods. Need to clean up some items in the model, then on to the upper platform. I doubt I have enough skills to correctly model a seat, pedals, and wheel, but I can at least get the mounts.

    Attached Files:

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  6. Mike Stuart

    Mike Stuart New Member

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    So, I guess I will need to edit my post title as I have decided to go with a 2DOF rig for now, and add later after the prototype is tested out. Based on conversations with my machinist buddy, I have revised the motor shafts for strength and upsized the actuator.

    Here is an updated picture. Can anyone comment on my actuator dimensions (attached PDF) as far as power from the pgsaw motors? Does the distance and adjustment seem correct?

    Next I'm moving on the the electronics for a while, as I wont have much time to do modeling. So, 2 more questions:
    1) Does the JRK 12V12 handle 2 motors?
    2) Which is the better unit as far as durability and ease of use, the JRK, or the Sabortooth 2X32, or somthing else? shaftmounting1.PNG shaftmounting2.PNG

    Attached Files:

  7. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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  8. Mike Stuart

    Mike Stuart New Member

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    Ok. Things are progressing. Made some more tweaks, Lowered the Seat platform, modeled in an OMP seat just for mock Finalassyrev1.PNG up purposes. added a footplate and actuator mounts. Ordering all of the steel and aluminum materials this week. (Upper portion is 6061 aluminum, lower is mild steel.) Hope to have some actual fabrication pictures for you guys in a couple weeks. Ordering all of the plates fully processed as i have cheap access to a waterjet, I will cut fabricate and weld the rest on my own.
  9. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Nice work.

    The closer the uni joint is to the actual seat base the better.
  10. Mike Stuart

    Mike Stuart New Member

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    I was actually just reading another thread that said to go higher with the actuator mounts, and angle the motors out and back more too. Looks like im going to do some more design changes.
    • Agree Agree x 2
  11. Mike Stuart

    Mike Stuart New Member

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    Ok, so hopefully getting close. Expanded base in order to spread out footing of motors in relation to the universal. Actuators have some angle now. Modified the seat universal joint to sit higher, thus closer to the seat. Giving the final go on material order tomorrow if anyone has any additional comments on the attached .pdf

    Attached Files:

  12. Mike Stuart

    Mike Stuart New Member

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    So finally enough steel came in to start the fabrication. Welded out the Steel components, will probably fit and weld the aluminum this weekend. Gear motors and pots ordered due in next week. Still mulling over a saber tooth 2X32 or the JRK's, leaning towards the saber tooth, but wondering if its going to be a good idea using a single PSU. Anyway, here's some progress pictures.

    20190314_094157_resized.jpg 20190320_145226(0)_resized.jpg 20190320_145226_resized.jpg 20190320_154921_resized.jpg 20190320_155549_resized.jpg
  13. Mike Stuart

    Mike Stuart New Member

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    Updates and some questions:

    1) Note to anyone using this model for the pgsaw motors. The file shows the output shaft hole as 1/2" in reality on the ones i got it is 12mm. I guess I have to rebuild my actuator shafts, going to go with the M12 threaded rod/nylock method. Hoping the couplers i bought for my hall sensors can just be shimmed.

    2) Also, I've decided to use the Sabertooth 12x32. This means one power supply. Can anyone lead me down the road to selecting the proper power supply to run (2) pgsaw 50:1's? Hopefully I dont need to use a battery or resistors others than those supplied to handle the back feed from the 50:1's.

    3) One other cautionary note. I noticed the screws in the gear motors seem very soft. Make sure you use the proper phillips size or you run the risk of stripping them easily.

    I Will have some nice update pictures after the weekend.
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  14. zapata_h

    zapata_h Member

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    the design of the structure is very worked, just nice
  15. Mike Stuart

    Mike Stuart New Member

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    Electronics have arrived. Might be a fun weekend, this definitely is not my strong point. I see a few questions in my future like how do i wire this relay?

    In picture:
    Dell server Power supply. 900W @110V input
    Sabertooth 2x32
    8 - 60 ohm resistors for motor feedback.
    Misc fuses with holders.
    Arduino Mega.
    Relay for start switch.

    Not shown:
    Hall Effect pots.
    Breakout board for power supply because i dont want to solder resistor, diode and transistor to the power supply. 20190328_172546.jpg
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  16. Mike Stuart

    Mike Stuart New Member

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    Update time. Mounted motors and decided to reverse them from the drawings. I still think I will need to bring the U-joint back towards the motors because to my eye it looks like the actuator shafts are going to clash with the arms (I am going to reverse the rod ends to the outside again, maybe rotate the motors inwards toward the u joint for more linear motion?). I will wait until the Upper assembly is mocked up to check either way I have lots of room to move back. Got a racing seat super cheap off ebay. 3d printed some standoffs for the sabertooth, and the arduino, printed a couple brackets for the power supply, and used Bixler13's file to print some pot brackets. All these files are available on thingiverse or the 3D printing forum here. Temp mounted the electronics to some wood for testing this weekend (please ignore the wiring, it is all getting redone this weekend - was just for testing PSU, Sabertooth, and arduino for power and rotation of motors.). Wish me luck we are getting close to software. Getting off the page a bit from all of my 3D modeling, but thats what happens in R&D right? So I wont be updating the model until the unit is complete, then I will post a complete 3D drawing to be sure we have accuracy.

    Question: How hot do these bridge rectifiers get? (I made a steel standoff for it.) Same Question for the resistors.

    20190403_163627_resized.jpg 20190404_170129_resized.jpg 20190404_170134_resized.jpg 20190404_172311_resized.jpg 20190404_172315_resized.jpg
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  17. zapata_h

    zapata_h Member

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    Can you attach the purchase link for those engines? Do you have to open them to isolate them from dough?
  18. Mike Stuart

    Mike Stuart New Member

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  19. zapata_h

    zapata_h Member

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  20. Mike Stuart

    Mike Stuart New Member

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    So on a sad note, I am scrapping the aluminum seat frame as I am not finding time to tig weld it out. I have decided to do an 8020 frame for the seat, pedals and wheel. This way I can get some adjustability, keep it light, and get it done faster. I will revisit the Aluminum frame at a later date, once I hav a final balance point. On a happy note, motors are up and running in simtools and very strong feeling. Updated pictures later this week hopefully with a seat attached.