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$450 Mige Direct Drive Wheel using MMOS and AASD

Discussion in 'DIY peripherals' started by Peacemaker105, May 6, 2020.

  1. Gadget999

    Gadget999 Well-Known Member

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    will the board have bluetooth / wireless connectivity ?
  2. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Not on board, but there are connections to the SPI2 port to attach an NRF52 bluetooth pair that is supported in the MMOS firmware.

    IMG_20200520_070706.jpg

    IMG_20200520_070521.jpg

    IMG_20200520_070441.jpg
    • Like Like x 3
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  3. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    I'm brutally honest on the video, showing some issues which are beyond me to fix (deadzone on spring for example). But then the fact that even using a 90ST motor could be enough for Direct Drive wheel...

    Its up to you guys to decide if its worth proceeding with this.

    • Informative Informative x 1
  4. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    @Peacemaker105 I seen these humming vibration as well, and using the DAC is the solution... :cheers

  5. Gadget999

    Gadget999 Well-Known Member

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    the oscillation in the wheel at rest - does this happen just as it passes the index ?

    can you dampen the output when the wheel passes the index ?
  6. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    My Motion Simulator:
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    So the motor has some inertia, and as soon it reaches the target position from the spring, it free wheels to the opposite direction and the spring gives torque command to move again to center. So it just moving forth and back near the target as there is no braking function to stop the motor right on target.

    Maybe @Peacemaker105 can verify his motor behave exactly the same? Or could be I have a bit older MMOS firmware loaded on the board (could not find the programmer this morning to update it).


    Last edited: May 20, 2020
  7. Gadget999

    Gadget999 Well-Known Member

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    when is the board available ? what is the target price ?
  8. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Don't know yet, given this is not my development, rather using MMOS firmware, and cannot improve it at will, its probably going to be mostly a kit, and low price. The thing bothering me is the shipping, as it will add cost.

    I'll have to think about it.
  9. Milt

    Milt Member

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    I'd be interested in picking up a board as well. I don't need the G27 peripheral connections so I could just use a Discovery board, but the DAC circuit would be tough to implement without a daughter board of some sort...
  10. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Yeah that's what I mean, the whole point of using this board is the DAC and the more compact Core407v. And the DAC is the second most expensive part actually after the Core407v...
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  11. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    I'll electrically check the DAC tomorrow, I think its offset a bit higher, as the reference voltage of the DAC is on 5v. I may have to hook it to 3.3v... perhaps the reason its bouncing near target (on desktop mode spring), it may not be going down to 0v...
  12. Peacemaker105

    Peacemaker105 Active Member Gold Contributor

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    What MMOS settings are you using? I haven't really played around with the spring test at that center position like that. I usually just adjust it in game and have had no issues whatsoever. as long as there isn't a deadzone in force feedback through the center i don't see a real issue here. You'll never be driving no hands (hopefully lol) But if you did you would have other forces affecting the wheel as well.. The spring back feels amazing and smooth when drifting and in rally. I'll have a play around with it tomorrow and see what mine does.

    I am really loving how well that DAC cleaned up the signal though!! Wow. I want!! save me a board please haha. Way easier to incorporate a DAC.

    Another thing i noticed while reading the manual.. When selecting encoder type it mentions 2500PPR.. i'm wondering if thats the only encoder or maximum encoder that the AASD would work with? Or are they just using it as a reference? Would there be any reason if you wired up a higher resolution encoder that it wouldn't be able to read it?

    encoder.jpg
  13. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Ok, checked the DAC and its completely fine. The servo receiver circuit get loaded a few extra mV load when it crosses the 0v point, but I found it can be fixed by setting a small negative torque offset with Pn190=-100

  14. Milt

    Milt Member

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    That might be a deal breaker this drive. Also from the drive specs in the manual they specifically call out the 2500p/r encoder.

    servo_screenshot.JPG
  15. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    I count 10000 pulses per 360 degrees, on my servos. The 2500 is quadrature resolution and useful for internal PID positioning in the drive, but does not really represents the actual resolution used by the MMOS controller!!! I'd say is not deal breaker, considering the low price of these servos.
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  16. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    The MMOS firmware does not benefit from using higher resolution encoder than 10000. The actual resolution used is perhaps 4096 points in the games (12bit).

    And sure one of these boards is reserved for you for $0 (plus shipping). Special price for you, for giving it a try :cheers
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  17. Peacemaker105

    Peacemaker105 Active Member Gold Contributor

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    It's definitely not a deal breaker by any means. I still think the wheel performs exceptional, especially for the cost. This is not meant to be a Simucube killer or anything but merely an alternative at half the cost with the option to go Simucube whenever you want in the future.
    • Agree Agree x 1
  18. Peacemaker105

    Peacemaker105 Active Member Gold Contributor

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    Thanks man! Legend. :)
    Honestly if i could get rid of that humm like the DAC will do then i don't see myself needing to upgrade anytime soon.
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  19. Milt

    Milt Member

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    Very true, I get ahead of myself and think big, but putting everything in perspective this is still a great solution.

    It's a shame that the MMOS firmware hasn't been released as open source. As far as I can tell the last release was in 2014 and development has stopped :(.
  20. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    True, but still nice to see its still relevant!!! :thumbs
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