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Question 2DOF Sim overshoot

Discussion in 'New users start here - FAQ' started by Pino Pistolidas, Jun 10, 2018.

  1. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    I just finished building my own 2DOF race simulator with Wipermotors, Arduino Uno and Monstor Motor Board.
    I'll send a new thread about this build soon.
    Communication and testing work well but as soon as a start with "Life for Speed" I'm getting overshoots.
    Mainly on the left side and the overshoot goes to the top (see picture).
    So my simulator leans to the right.
    I have added pictures of my settings.
    I hope someone can give me some advice and or suggestions.

    Rgdrs,

    Pistolidas Overshoot.jpg

    Attached Files:

    Last edited: Jun 10, 2018
  2. Ads Master

    Ads Master

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  3. JonBakhol

    JonBakhol Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, JRK
    Hi pino,

    Your Kd is very high. Not sure if there is the trick for not overshooting?
    Maybe @noorbeast can take a look at it and put you in the right direction.

    Wondering how your thread will be.
    • Agree Agree x 1
  4. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
    3DOF, DC motor, JRK
    I agree with @JonBakhol your SMC3 settings need refinement as there looks to be overshoots.

    To simplify matters while being it sorted I would suggest clearing the Startup and Shutdown fields in the interface settings.
  5. sam poole

    sam poole Active Member

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    My Motion Simulator:
    3DOF, DC motor, Arduino, Motion platform, 4DOF, 6DOF
    Just for comparison my Kd is set to 1 with wiper motors and give no overshoot
  6. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Thanks all for the intput, but I'm afraid the overshoots still happen.
    What I found out is it looks like the motors aren't pulling down hard enough.
    So if the seat leans left it's really easy to push the right motor into a top overshoot.
    The same happens when the seat leans right , than it's really easy to push the left motor in a top overshoot.
    So the motors push up hard enough but they hardly pull down.
    I have attached a file where you can see it happening in SMC3.
    I hope my explanation makes sense, i tried a lot of settings but I couldn't find any improvements.

    Hope someone can help me with this matter.

    Attached Files:

  7. sam poole

    sam poole Active Member

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    My Motion Simulator:
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    Have you wired the motors at opposing brushes?
  8. MarkusB

    MarkusB Active Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    Well, when the seat leans to the left, the weight of the seat helps the right motor to move upwards by pulling at the rod connected to the right motor. The larger the seat angle, the larger is the force that the seat applies to the motor, and the harder it is for the motor to move the seat back into its neutral position.

    So maybe your wiper motors are just too weak to move the seat back? Is it a shoulder mounted rig?

    You could try to decrease the Axis Limiting further, which will reduce the max angle of the motors.
    • Agree Agree x 1
  9. sam poole

    sam poole Active Member

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    This would effect in this way I imagine if the rig wasn't balanced presumably it has been balanced ?
  10. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    My Motion Simulator:
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    Thanks for your inputs.
    I have indeed not used the opossing brushes.
    This sounds like a feasible explanation I'll rewire them and see if this helps.
    It is indeed a shoulder mounted rig and I did my best to get my rig as balanced as possible.
    Also I tried to have the right angles on my push rods.
    I'll send an update soon.
  11. sam poole

    sam poole Active Member

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    My Motion Simulator:
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    Also worth noting the casing of the motors should be isolated from each brush if mounted to the same metal as each other
  12. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    I rewired the wiper motors, so I'm now using the opposing brushes and this made a mayor improvement.
    I also shortened the rods between the motor and the shoulder mounts and this also helped.
    And if I keep the axis limitations at 35 I'm no longer getting overshoots when playing Life for Speed.

    Thanks for all your help
    • Like Like x 1
  13. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    The overshoot problems where due to a faulty Monstor Motor Shield. (I'm not the first when I read different threads)
    I have been playing different games and ones in a while I still got an overshoot.
    I swapped the motors and it was still on the same side. But when I swapped the polarity to the motor the problem went from overshoot to undershoot.
    So one direction of one of the sides from the MM board was faulty.
    I replaced the MM board and now it's much much better.

    I ordered a DBH-01C from Aliexpress https://www.aliexpress.com/item/1PC...e-module-high-power-H-bridge/32747943206.html to use insted of the MM board, I'll give an update on this soon.