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My project 2DOF plus Traction loss

Discussion in 'DIY Motion Simulator Projects' started by chrisgeo, Jul 1, 2020.

  1. chrisgeo

    chrisgeo Member Gold Contributor

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    Hello noorbeast,

    First of all thank you for moving the post to the place were it belongs.

    Here are the answers to your questions:

    #1: Sometimes it happens straight away when I activate the output testing, sometimes a while into the testing, I could not find a way to reproduce the behaviour, it appears to happen randomly and only one motor is affected.

    #2: In regards of your idea of the SMC3 configuration issue, what could it be? I took the latest SMC3 version and changed it to "Mode 2" for the use of IBT2, but nothing else.

    #3: The settings are the standard settings in SimTools for the connection to the Arduino and for everything else I will post the screenshots shortly.

    Thank again.
  2. chrisgeo

    chrisgeo Member Gold Contributor

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    Hello,

    here are the screenshots for the settings of my setup. I hope this might help you to identify the issue I currently
    have with my rig.

    picture1.JPG picture2.JPG picture3.JPG picture4.JPG picture5.JPG picture6.JPG picture7.JPG picture8.JPG picture9.JPG picture10.JPG
  3. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    I would suggest a back to basics approach.

    First refine the SMC3 settings, you want the green line to track the blue as close as possible and in particular set the Max Limits and Clip Input to control the range, see the functional explanations here: https://www.xsimulator.net/communit...driver-and-windows-utilities.4957/#post-48121

    Once SMC3 if fully sorted then you can start with SimTools, grab a copy of the SimTools manual and keep it handy for reference: https://www.xsimulator.net/community/faq/rtfm-start-with-the-official-simtools-documentation.117/

    Initially do not use filters or limit axis, instead initially dial in each axis individually, before enabling them all and tweaking from there, see the tips here: https://www.xsimulator.net/community/faq/steps-to-create-a-motion-profile.228/

    Be mindful of the Axis Assignment % totals: https://www.xsimulator.net/community/faq/axis-assignment-percentage-totals.120/
  4. chrisgeo

    chrisgeo Member Gold Contributor

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    Here is a link/video for the first movement test of my rig.

  5. chrisgeo

    chrisgeo Member Gold Contributor

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    And here is a video of the issue i currently have, with one of the motors going into a position beyond the set range.

  6. chrisgeo

    chrisgeo Member Gold Contributor

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    noorbeast, thank you.

    I followed the SMC3 manual and the result was/is the collapsing behaviour for motor #1, I changed the IBT2, checked and adjusted the rotation sensors.

    So I will reset most settings and start from scratch,
  7. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    As mentioned you need to set the SMC3 Max Limits and Clip Input to control the range., along with refining SMC3 PID settings.
  8. chrisgeo

    chrisgeo Member Gold Contributor

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    Me again,

    I did all what was recommended above, but it did not help with my issue.
    However, I found that when the motor collapses the PWM signal becomes very high and flatlines as see in the screenshots below. Before this happens all works as expected. I also played with different settings form the one suggested in the manual to many others, the behaviour is always the same.

    I even rewired some cables, because I thought the issue might be bad cabling.

    I am a bit lost the moment and help would be much appreciated.

    Thank you.

    SMC3_settings.JPG
    Screenshot with settings


    SMC3-Capture-74653.4134722_LI.jpg
    Motor #1 at the moment of the collapse


    SMC3-Capture-74411.9732276_LI.jpg Motor #2 at the moment of the collapse
  9. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    On the mechanical side how long is the lever CTC?

    Try a CTC of 50-60mm.

    In addition a lever becomes inefficient in terms of torque over about 38 degrees up and down.
  10. chrisgeo

    chrisgeo Member Gold Contributor

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    At the moment the lever is 100mm and once the mechanics is sorted I will limit the
    movement to 35degrees, this is the way I calculated it.

    I will check the shorter lever and come back with the result.
  11. chrisgeo

    chrisgeo Member Gold Contributor

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    Any idea why the PWM signal goes flat?
  12. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    I would expect it is triggered by a disconnect.
  13. absyfadhel1

    absyfadhel1 Member

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    My Motion Simulator:
    2DOF, Arduino
    Try set PWMAX to 140-170,

    because my motor turn off when there is heavy movement with more than 170 PWMAX , so try lower it maybe it help,

    using 2x IBT-2 as for one motor helped me alot , look at this thread https://www.xsimulator.net/communit...-a-single-motor-driver-more-power.5482/page-7
  14. chrisgeo

    chrisgeo Member Gold Contributor

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    Here is an update from my rig, I was able to drive 10min today without issues and without major changes to the rig itself. So what did I change?

    First I installed some small heatsinks on both the BTS7960 chips of the IBT-2 controllers.
    They look a bit funny, because I had to divide a bigger to fit the size of the chips.
    IMG_1937.JPG

    The second thing I did, was to wrap the power cables and the wires between the IBT2 and the Arduino through some ferrite rings.
    IMG_1939.JPG

    IMG_1940.JPG

    These action improved the data signal quality significantly, I will post a screenshot here in the next few days.

    I will also post my new settings for SMC3Utils, thanks to @absyfadhel1 and his ideas.

    Working on the rig are now, the left and right motor, the bass transducer (buttkicker) and the fans for wind simulation.

    To do: Traction loss, it is technically working, however the rollers I currently are not good enough and the friction is to high. I will replace them with heavy duty ball bearings. Also not finished yet, is the seat belt tensioner, because the motor I planned to use, is electrical not isolated, so back to the drawing board for this one.

    Once everything is working, I will transport it back to the workshop to change a bit on the sim rig, like improvement to the balance and centre of gravity, shorten the front overhang. reposition the handbrake and other smaller stuff.
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  15. chrisgeo

    chrisgeo Member Gold Contributor

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    So as I said before, it appears that I was able to rectify the issues I had with the IBT-2 controllers.

    Here is a short first video of it moving. Far from finished, but it is moving!!!

  16. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
    3DOF, DC motor, JRK
    Great to see your rig is moving, well done :thumbs

    See here for tips on how to refine your motion profile: https://www.xsimulator.net/community/faq/steps-to-create-a-motion-profile.228/

    You probably need to also refine your SMC3 settings further as there is too much range for effective use of torque, better to have greater responsiveness over a smaller range, over about 38 degrees up and down is inefficient with respect to torque utilization:

    Past range.jpg
  17. chrisgeo

    chrisgeo Member Gold Contributor

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    @noorbeast, thanks again for the information, every single bit is very useful.

    My first goal was to make sure everything basically works, when this is achieved I will take the rig back to the workshop and implement the needed changes, such as change to the balance, shortening of the the front bit, and just the seat position. Once this is all done, then the rig will be finally welded together and probably powder coated as well. Once this is all done and the rig is back at home, then I will do the fine tuning including the restriction of the movement angle.

    Thank you for all your help so far, it is much appreciated!
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