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Showroom WKOM 6DOF AC Servo Motion Platform

Discussion in 'DIY Motion Simulator Projects' started by Wojciech Komorniczak, Aug 21, 2019.

  1. Wojciech Komorniczak

    Wojciech Komorniczak [Voyteck]

    Joined:
    Dec 15, 2018
    Messages:
    17
    Location:
    Warsaw, POLAND
    Balance:
    24Coins
    Ratings:
    +51 / 0 / -0
    My Motion Simulator:
    AC motor, Arduino, Motion platform, 6DOF
    I use step/dir position mode. The current state of the angular servo position is processed and stored in Arduino controller. It looks like, even after 2 hours session under full load, no step is missing.

    I squeezed the servo controllers inside a typical midi tower PC case (Fractal Design - Core 3500 Window). Take a look a the pictures below. I also removed the noisy fans from the AC servo controllers and installed 4 slow and quiet 14 cm fans on the case walls. You can barely hear it working, while the controllers are kept cool.
    When I took the picture, I noticed the thick layer of the dust on the case top. It's a message: the rig is working flawlessly, no need to touch the control unit ;)

    Cheers from Warszawa :)

    IMG_0184.jpeg IMG_0186.jpeg
    • Like Like x 5
  2. Sun woong kim

    Sun woong kim New Member

    Joined:
    Dec 19, 2018
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    Balance:
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    My Motion Simulator:
    DC motor, AC motor, Arduino, 4DOF
    Hi friend~~

    I'm interested in your torque arm.

    would you please upload your CAD file?

    thanks in advance.
  3. Wojciech Komorniczak

    Wojciech Komorniczak [Voyteck]

    Joined:
    Dec 15, 2018
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    17
    Location:
    Warsaw, POLAND
    Balance:
    24Coins
    Ratings:
    +51 / 0 / -0
    My Motion Simulator:
    AC motor, Arduino, Motion platform, 6DOF
    I attached Fusion360 export file and .step file. The basic drawing is below (milled in 12 mm aluminum sheet):
    Zrzut ekranu 2019-09-24 o 13.25.20.png

    Attached Files:

    • Like Like x 1
    • Useful Useful x 1
  4. Wojciech Komorniczak

    Wojciech Komorniczak [Voyteck]

    Joined:
    Dec 15, 2018
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    Location:
    Warsaw, POLAND
    Balance:
    24Coins
    Ratings:
    +51 / 0 / -0
    My Motion Simulator:
    AC motor, Arduino, Motion platform, 6DOF
    A couple of pictures of the servos being attached to the lower part of the frame:

    IMG_0648.jpeg IMG_0649.jpeg IMG_0650.jpeg
    • Like Like x 5
  5. Sun woong kim

    Sun woong kim New Member

    Joined:
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    My Motion Simulator:
    DC motor, AC motor, Arduino, 4DOF
    thank you for your kindness~~~
  6. lromaniuk

    lromaniuk bny

    Joined:
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    Your case looks very neat. I was planning to put servo amplifiers in a rack cabinet of size 600x450 mm. My aplifiers have only radiators (and braking resistors) so my thinking was that they need some room to prevent overheating, but I havent tested tchem with real loads. Maybe your case solution will also work for me (less space taken by the cabinet - easier to carry). Thanks for the pictures!

    I'm very curious about your controll method, espetially how do you generate step signal? I have finished analog speed control mode but it requires additional IC'c (I'm using 12bit DAC and some expensive Aplifier to bring control signal to required +/- 10V range) thus when @Thanos presented its new firmware and controller that uses step/dir I'm thinking to transition to this kind of control scheme. What bugs me is how to properly generate step signal. My initial test where simple direct pin manipulation, just to see if it works, but I imagine that that signal won't have stable pulse frequency (I have no idea if it's even a requirement to have stable pulse frequency). My next thougth is to youse timers to generate required numer of pulses with desired frequency, but it's over my head for the moment. It would be awesome it you could share some details about how you are dealing with pulse generation?
  7. BM114

    BM114 New Member

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    First off I wanna say that I am impressed by just how neat your simulator turned out. You've done a great job on it.

    I did want to ask about the AC servo system though.

    At first glance the motor setup appears to be $550 per motor/driver/gearbox. Which would end up as a project cost of about $4-5k USD. Is that correct?

    Do you have any issues with backlash when you reverse direction? I always wondered if it was noticable with the lever arm style and a lowlash planetary gearbox.

    I'm planning a pretty slim budget for my first build, but I like to know my options when I got for the MK2 variant. Thanks!
  8. Wojciech Komorniczak

    Wojciech Komorniczak [Voyteck]

    Joined:
    Dec 15, 2018
    Messages:
    17
    Location:
    Warsaw, POLAND
    Balance:
    24Coins
    Ratings:
    +51 / 0 / -0
    My Motion Simulator:
    AC motor, Arduino, Motion platform, 6DOF
    @BM114 In fact, I paid $3k USD including quite an expensive shipment cost from CN to PL (see the attached costs summary). The cost of the remaining pars was below $600 USD.
    Zrzut ekranu 2019-10-1 o 00.25.58.png

    The backlash: I intentionally bought the planetary gearboxes to avoid the backlash and it worked. When I try to move the servo arm manually in both directions, I can feel no backlash. I suppose, the worm gear system gives a substantial backlash compared to a planetary gearbox.
    • Informative Informative x 1
  9. Wojciech Komorniczak

    Wojciech Komorniczak [Voyteck]

    Joined:
    Dec 15, 2018
    Messages:
    17
    Location:
    Warsaw, POLAND
    Balance:
    24Coins
    Ratings:
    +51 / 0 / -0
    My Motion Simulator:
    AC motor, Arduino, Motion platform, 6DOF
    @lromaniuk Regarding the pulse generation, I noticed that the AC Servo Controller is not sensitive to the pulse period fluctuations. It just counts the pulses and moves the servo the preprogrammed number of the internal encoder "clicks". Actually, the only thing you should pay special attention is the minimum pulse repetition period. In my case, it was something around 20 microseconds. Below that value, the servo movement was kind of jerky. For each servo, I use two digital outputs of my Arduino: one for the pulses and the other one for the DIR (direction) signal. Indeed, it took some time to tune the control method on the bench but the result is absolutely satisfying.
    • Informative Informative x 2
    Last edited: Oct 1, 2019
  10. fluffybunnyman

    fluffybunnyman New Member

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    Really impressive platform, I am thinking about creating my own based on your design! Would you mind sharing the basic dimensions of your base and rod arms and platform that I can use as a starting point?