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MMOS controller with cheap servo drive and motor

Discussion in 'Direct Drive Wheels' started by sikjar, May 22, 2017.

  1. Alexey

    Alexey Well-Known Member

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    I can answer point 1 !!!!! :)

    From one of my side projects:
    This averaging is due to a tiny jitter in the input signal which would cause the motor to vibrate into position rather than go smoothly in one direction.
    I saw this exact thing happen when I was reading a position target value and there was a bit of noise on the input line which caused the motor to become unstable.

    Essentially this acts as a "smoothing" function,
  2. Gadget999

    Gadget999 Active Member

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    Do you think the lack of resolution is actually to do with the windings inside the motor and how they are spaced apart ?

    Is this a dc bushed motor ?
  3. Alexey

    Alexey Well-Known Member

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    Stepper motors will normally have a 1.8 degree spacing per step and so that is where the "cogging" feeling comes from. To counteract this you can use something called micro stepping where you tell the motor to step froward but not quite fully forward. This is done by partially energizing two coils instead of one. This type of control can go as low as 1/16th of a step. While this may smoothen out the cogging that is felt it can drastically reduce the amount of torque available from the motor as the coils are not fully energized. To add more torque back into the motor a higher voltage is used, typically larger than 48V and usually above 70V.
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  4. Gadget999

    Gadget999 Active Member

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    is the motor a stepper motor or a AC/DC syncro motor ?
  5. Alexey

    Alexey Well-Known Member

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    The motor is a stepper motor
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  6. sikjar

    sikjar Xiao Nie

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  7. sikjar

    sikjar Xiao Nie

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    Hi, a late reply to the above:
    1. I collect 10 samples to smooth out any spikes there may be in the FFB signal. I tried leaving this part of the script out, and it doesn't actually seem to make much of a difference.
    2. I set the torque to zero before changing the direction of the force, to avoid having the force feedback suddenly jolt in one direction, and the the other direction.
    3. The torque is only set to zero at startup initialization and when the direction changes.
    Hope this answers your questions.
  8. ahoenksiluman

    ahoenksiluman Member

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    can you see leadshine EL5-D1000...??

    can it be the motor driver..??
    that driver have much mode and feature...
    maybe it can work like argon driver...

    sorry for bad english...
  9. sikjar

    sikjar Xiao Nie

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    I don't know, never tried the EL5-D1000. But you wold probably have to change the hex code sent via serial in order to make it work.
    If the EL5-D1000 can change the torque output based on a PWM signal, the you don't need the arduino, you can use it like an Argon driver.
  10. MegamanAT

    MegamanAT New Member

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  11. MegamanAT

    MegamanAT New Member

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  12. MegamanAT

    MegamanAT New Member

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    Seems like those drivers can't handle pwm input. So they probably wont't work with mmos.
  13. MegamanAT

    MegamanAT New Member

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    After reading the manual, I don't think the EL5-D1000 can accept pwm as input. Seem like not even a single servo driver on aliexpress can do this.
  14. MegamanAT

    MegamanAT New Member

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    Your arduino project seems to be like the last chance for a cheap dd-wheel.
    Last edited: Nov 29, 2017
  15. Gadget999

    Gadget999 Active Member

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    can you program a chip to convert the pwm to the signal the servo will accept

    what type of signal do you need ?
  16. MegamanAT

    MegamanAT New Member

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    No. But that is exactly what is done with the arduino here. Mmos only outputs pwm but the cheap drivers can only use pulse + direction. The only other option would be this project: https://www.xsimulator.net/community/threads/son-of-opensimwheel-an-experiment.7422/

    But the problem is, RufusDufus won't share details of his approach because he want's to sell his controllers. But on the other hand, he just only made a handful of them... But you can ask him, if he will put you on his list. But don't expect to much: I am waiting since March...
  17. Gadget999

    Gadget999 Active Member

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    are you using a stepper motor ?
  18. MegamanAT

    MegamanAT New Member

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    At the moment, I am using neither a servo, nor a stepper motor. I wanted to use a stepper motor with the controller from rufusdufus, but since this project seems to be dead, I wanted to build a cheap OSW based on Chinese hardware from aliexpress. Unfortunately, none fo the stepper drivers can handle pwm inputs, so unless we find a solution for that, we will have to stick with argon or simucube/ioni. I am not a hardware engineer at all. Only a software engineer;).

    But maybe we could convert the digital pwm signal to an anolg signal to feed the driver?
  19. MegamanAT

    MegamanAT New Member

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  20. Gadget999

    Gadget999 Active Member

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    does the driver need a 0-5v output ?