1. Do not share user accounts! Any account that is shared by another person will be blocked and closed. This means: we will close not only the account that is shared, but also the main account of the user who uses another person's account. We have the ability to detect account sharing, so please do not try to cheat the system. This action will take place on 04/18/2023. Read all forum rules.
    Dismiss Notice
  2. For downloading SimTools plugins you need a Download Package. Get it with virtual coins that you receive for forum activity or Buy Download Package - We have a zero Spam tolerance so read our forum rules first.

    Buy Now a Download Plan!
  3. Do not try to cheat our system and do not post an unnecessary amount of useless posts only to earn credits here. We have a zero spam tolerance policy and this will cause a ban of your user account. Otherwise we wish you a pleasant stay here! Read the forum rules
  4. We have a few rules which you need to read and accept before posting anything here! Following these rules will keep the forum clean and your stay pleasant. Do not follow these rules can lead to permanent exclusion from this website: Read the forum rules.
    Are you a company? Read our company rules
Shared accounts will be removed Plugin Downloads Zero spam policy Forum Rules

Question 2DOF project

Discussion in 'DIY Motion Simulator Projects' started by Andrej263, Mar 24, 2025 at 22:56.

  1. Andrej263

    Andrej263 New Member

    Joined:
    Nov 27, 2024
    Messages:
    5
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    Hi everyone,

    I’ve run into an issue with my project involving a motor and a potentiometer. I have assembled the frame for a chair, wired everything up, and got it ready, but during testing, I noticed that the potentiometer doesn’t move correctly when the motor moves.

    Specifically, the problem is that the potentiometer value "jumps" out of the expected range, and unless I manually adjust it back, the system doesn’t work properly. Even when I adjust it, the issue repeats itself after the motor moves again.

    Interestingly, when I had the system running with a gear ratio using gears, everything worked fine. However, after switching to a direct connection, the issue started happening.

    Has anyone encountered something similar? What could be causing this issue, and how can I fix it?

    Thanks for any advice!

    upload_2025-3-24_22-55-1.jpeg
    Andrej263, Mar 24, 2025 at 22:56
    #1
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    21,428
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    150,223Coins
    Ratings:
    +11,000 / 55 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    noorbeast, Mar 25, 2025 at 01:52
    #2
  3. Andrej263

    Andrej263 New Member

    Joined:
    Nov 27, 2024
    Messages:
    5
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    I isolated the motor in a different way—I didn’t cut the brush that connects it, but instead used spacers, so I think that shouldn’t be the issue. Both motors were moving simultaneously.

    My computer is not set to English Locale.

    Here are my settings:

    Attached Files:

    Andrej263, Mar 25, 2025 at 07:03
    #3
  4. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    21,428
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    150,223Coins
    Ratings:
    +11,000 / 55 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    The pot does not seem to be centered. You could try disconnecting power to the motor, disconnect the pot and rotate it by hand so that it is centered when the motor levers are ion their central position.

    How did you come to the SMC3 settings you have? This is the normal initial setup routine, at what PWMmax does the motor start to move: https://www.xsimulator.net/communit...3dof-motor-driver-and-windows-utilities.4957/

    Disconnect the motor power supply
    Make sure Simtools is not running – we’re not ready for that yet!
    Wire up the Arduino (with SMC3 installed) to your H-Bridges and connect to your computer via USB
    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)
    Set the Kp, Ki, Kd, PWMmin, PWMmax, PWMrev to 0 for ALL motors (This will make sure the motors don’t move)
    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)
    Turn on the power to your motors – nothing should move at this stage!
    Set Kp to about 400
    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.
    Do the above for each motor
    noorbeast, Mar 25, 2025 at 09:29
    #4
  5. Andrej263

    Andrej263 New Member

    Joined:
    Nov 27, 2024
    Messages:
    5
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    I disconnected the potentiometer and tried the settings as described. The problem is that my motor starts running even at a low Kp. When I set it to 400, the motor keeps running continuously and doesn’t approach the target or anything. I don’t know what I did wrong.

    Of course, when I move the potentiometer, it reads the values correctly, but it seems like it’s linked to a different motor or a different potentiometer—I’m not sure. I already tried swapping them, but then it showed the values in reverse. So I have no idea where the issue could still be.
    Andrej263, Mar 25, 2025 at 17:40
    #5
  6. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    21,428
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    150,223Coins
    Ratings:
    +11,000 / 55 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Are you saying the motors move with PWMmax set to 0?

    If so I would suspect potentially faulty hardware, what control boards are you using?
    noorbeast, Mar 25, 2025 at 22:51
    #6
  7. Andrej263

    Andrej263 New Member

    Joined:
    Nov 27, 2024
    Messages:
    5
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    I managed to fix it, and I set the parameters like this. I'm not sure if it's completely correct, but it seems to be running quite smoothly.

    upload_2025-3-26_11-21-10.png upload_2025-3-26_11-21-47.png
    Andrej263, Mar 26, 2025 at 11:21
    #7
  8. Andrej263

    Andrej263 New Member

    Joined:
    Nov 27, 2024
    Messages:
    5
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    Can I set the default position of the seat somehow? Because whenever I try to test it, it automatically moves to the position shown in the picture.

    Attached Files:

    Andrej263, Mar 26, 2025 at 12:21
    #8
  9. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    21,428
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    150,223Coins
    Ratings:
    +11,000 / 55 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    The levers should be centered in the SMC3 graph while being in the correct position to level the rig in its default position.
    noorbeast, Mar 26, 2025 at 12:26
    #9