avoid T axis rotation

    Dear all,

    I am having trouble while trying to create a circle movement with my Yaskawa GP25 robot arm, both on the Motosim software and in real life with the robot. I created 3 points in a userframe (start point, passage point 1 and passage point 2, all with the same orientations), and 4 MOVC movements in the programm:

    - MOVC Start_point

    - MOVC Point1

    - MOVC Point2

    - MOVC Start_point

    2 questions :

    - The robot briefly stops at each passage point : is there a way to get a continuous mouvement ?

    - The T axis spins 1 turns for the last MOVC leading the robot to stop due to T axis exceed limits, why this rotation and is there a way to avoid it ?

    The tool is straight from the flange (200mm Z offset only).

    Thanks in advance for any help.

    Regards

  • MOM April 19, 2024 at 10:59 AM

    Approved the thread.

    No, position variables are defined in userframe with X,Y,Z coordinates and orientation.

    What surprises me is that there is no rotation between :

    - start point and point 1

    - point 1 and point 2

    hence there should be none also between point 2 and start point !

    The idea is to keep the userframe to adapt the path, so this means I need to convert the points in pulse before the MOVC, rigth ?

    I can try this, however I hope there might be a simple option I miss ...

    regards

    To BCinTN : You mean up/down, lefty ... ? Yes, all 3 points are in the same position. Plus, end point of the circle is the start point, not only same coordinate but same point. Moreover, points are spaced of less than 200mm and in an easy reachable location.

    To TSGIR : Maybe I am misunderstanding or misexpressing myself. I created a userframe, adapted to the support. I created 3 points variables in this same userframe. The idea is to adapt the location of the moves depending the support location and orientation. Am I getting wrong somewhere ?

    Regards

    Yaskawa_UTT, if I understood correctly, your first and last points of the circle are identical. But this is incorrect, since when passing the circle the robot changes its configuration. For example: at the first point of the circle the T axis has a position of -180 degrees, and at the end point of the circle 180 degrees. Thus, for one circle you need 4 points, since the first and last points are actually different.

    Below I described how to create the last point of the circle:
    -being approximately at the starting point of the circle (MOVC Point 1)
    -manually rotate the T axis by 360 degrees
    -using FWD to come to the point (MOVC Point 1), an error will occur
    -reset the error
    -save this position as a point (MOVC Point 4)

    Сorrect type of program:

    - MOVC Point1 (Start_point)

    - MOVC Point2

    - MOVC Point3

    - MOVC Point4 (End_point)

    To answer question 1, use the PL to set the accuracy of the position. By adding in a PL the robot will get close to the exact point but won`t try to be perfect. PL values are between 0 and 8 with 0 being perfect. You can try out which one fits best, but I usually use between 1 and 3.

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