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Thread: Dynamixel AX12A Strange problem

  1. #1
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    Dynamixel AX12A Strange problem

    Hi,

    I have an AX12A with a strange problem, when the angle is set below 100 it just keeps rotating and doesn't stop. It works fine with angles from 101 > 1023. I've tried resetting the servo and re-flashing the firmware but that doesn't work.

    Any help would be appreciated.

  2. #2
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    Re: Dynamixel AX12A Strange problem

    If both the CCW and CW angle limits were set to 0, then it would be in continuous rotation mode, but it should never switch between servo and wheel modes just by sending a goal position. It sounds a bit like there may be an issue with the potentiometer's wiper in one portion of its range, producing a voltage the firmware cannot handle as if it were in the no-go zone of a well functioning potentiometer.

    Does it rotate in only one direction after sending it to sub-100 positions? If you send it to 50 then 75, does it change direction of
    rotation? Might have to send it to Robotis for repair/replacement or set the CW limit angle above 100 to prevent it reaching the hazardous portion of the servo range.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  3. #3

    Re: Dynamixel AX12A Strange problem

    My guess would be that it loses contact with the wiper at position 100 or so, and thus can't quite tell where it is. There may be some additional resistance that makes it think it's always at position 110, too.

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    Re: Dynamixel AX12A Strange problem

    Thanks for the replies, I think it probably is the wiper pot.

    I managed to swap that servo the the gripper on my robot arm, I don't need the full travel so it should work fine.

  5. #5

    Re: Dynamixel AX12A Strange problem

    richard347, it sounds like you've got it under control, but if you'd like I can help you send the servo back to ROBOTIS for repair - they offer a 1 year warranty on all their servos. Just shoot me a message.

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