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Question First 2DOF SIM Rig with issues 24V wheelchair Motors

Discussion in 'DIY Motion Simulator Projects' started by Bjoern, Feb 18, 2024.

  1. Bjoern

    Bjoern New Member

    Joined:
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    My Motion Simulator:
    2DOF
    Hey,
    I have some issues with my first Sim Rig projekt.

    my Setup:
    2x 24V Wheelchair Motors 250W 75rpm
    2x IBT_2 BTS7960 43A Dual H-Bridge
    1x Arduino Uno
    1x 800Watt 24VDC Powwer Supply

    I have done the wiring and and have load the sketch to the Arduino.
    My issue is that both motors are only spining in one direction. I have tested several settings in the SMC3 Tool and always the same results only one direction. I had checked the wiring three times.
    Pherhaps the mode in the Arduino is "MODE2".
    Maybe the IBT_2´s are brocken but both?

    Any Ideas what going on here?

    Thx and Regards
    Bjoern
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    Ratings:
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    My Motion Simulator:
    3DOF, DC motor, JRK
  3. Bjoern

    Bjoern New Member

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    My Motion Simulator:
    2DOF
    Hi,
    yes the pots are working fine, if I spin them with my hand i can see every little motion at the SMC screen, and of course they are connected to the Motors.

    Here are a video of my issue:

    Attached Files:

  4. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    +10,778 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    It does not look like everything is properly centered at rest before calibration.
  5. Bjoern

    Bjoern New Member

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    yes, in the video is was not centered, but it makes no difference if centered or not.
    Here a video with centerd position of the pot

  6. Bjoern

    Bjoern New Member

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    My Motion Simulator:
    2DOF
    If i swap the cables at Rpwm and Lpwm at the motor controllers should the motor spin in the other direction?

    Because nothing happens if i do this.
  7. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    Balance:
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    Ratings:
    +10,778 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Try testing the IBT2s with a multi-meter, to see if they work as expected.

    If so please set Fpwm to 25 and do the calibration sequence from scratch, then post the result, including the value of PWMmax when the motor begins to move:
    1. Disconnect the motor power supply
    2. Make sure Simtools is not running – we’re not ready for that yet!
    3. Wire up the Arduino (with SMC3 installed) to your H-Bridges and connect to your computer via USB
    4. Run the Windows SMC3 Utility software and make sure it communicates with the Arduino (There is no need to set baud rates, they are not configurable)
    5. Set the Kp, Ki, Kd, PWMmin, PWMmax, PWMrev to 0 for ALL motors (This will make sure the motors don’t move)
    6. Set Clip to 255 (you need to do this first) and Limit to 255 (This will give you plenty of margin if something goes wrong while setting up)
    7. Turn on the power to your motors – nothing should move at this stage!
    8. Set Kp to about 400
    9. Now slowly, increase PWMmax… at some point the motor should start to move. When it does check the “Green” feedback line is moving toward the “Blue” target position.
      • If it is then that motor and feedback is wired correctly - proceed to test other motors.
      • If it is moving away turn off motor power immediately (or quickly reduce PWMmax again). In this case you need to either reverse the wires to the motor being tested –OR– reverse the +5V and GND wires to your feedback pot for the motor being tested (do not do both). Restart the test from the beginning.
  8. Bjoern

    Bjoern New Member

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    My Motion Simulator:
    2DOF
    Ok, somthing is strange

    If i do the setup routine and set the Parameters as in the description the motor is spining.
    The yellow line (PWM) is staying at 0 but the motor ist spinning. PWMmin and PWMmax are at 0.

  9. Bjoern

    Bjoern New Member

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    My Motion Simulator:
    2DOF
    Also when i set KP to 0 i can spin the motor, whats is wrong here?
  10. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
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    Balance:
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    Ratings:
    +10,778 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Did you test the IBT2?
  11. Bjoern

    Bjoern New Member

    Joined:
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    My Motion Simulator:
    2DOF
    Yes, the ibt_2 are working only in one direction. When they had do reverse i messure 0Volts at the Motor pins.
    I also messured the PWM pins, there it seems all is fine. The voltage increase when i spin the pot away from center and decrease when i spin it to the center position. This works in both directions.
    I guess the IBT_2 are defect, but i am perplexed that both are defect.

    Have u got an explanation about this:
    Also when i set KP to 0 i can spin the motor, whats is wrong here?
  12. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,551
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    145,124Coins
    Ratings:
    +10,778 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    A number of members have reported faulty IBT2s, so manufacturing standards could be an issue, as they are built to a price.
  13. Bjoern

    Bjoern New Member

    Joined:
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    My Motion Simulator:
    2DOF
    The twoIBT´s are broken, i changed them and everything works.

    Thanks for the support
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