Mill with an 7 axis

  • Hi to all!

    I want the robot to mill the element using the external axis. The expected behavior is: the robot approaches, takes position and then the external axis turn, then the robot change position and the external axis turn back and so on until the end of the program.
    In the program, everything works very good, but in real, the table rotates in the one direction, the robot in the other.

    The table is calibrated, when the table rotates in T1, the cutter moves behind it.

    Do you have any suggestion to solve this?

    Info :

    KUKA KR210-L180-2

    KRC 2 V5.5

    Software RoboDK

    Thanks in advance

  • AD
  • Well I am guessing in RoboDK and on KUKA the external axis are setup differently. But I am very confident the robot behaves exactly as it should given its configuration and its given robot program. Hence I would check if the RoboDK setup is correct.


  • Maybe you can help me setup external axis on KUKA? In rodoDK I have configuration so that when the table rotates, the coordinate system rotates too. The robot, in order to stay in place, compensates for the rotation of the table by rotating in the opposite direction of the axis A


  • Hello Fubini

    Thank you very much for information, I am read and correct my configuration, but robot don't work.

    This is my code, maybe it is wrong

    Maybe you can help me?

    Thanks in advance

  • As far as I can see you might not activate a base moving with the table. Line 22 activates a static base. Lookup $bas.src what happens if you call BAS(#BASE, 17). Does a EK get called or not? You could also check if a moving base is active if you halt your programm after line 24 and jog the table with an active cartesian base coordinate system. It should drag along the robot if active. If the robot remains at a hold it coupling of robot and moving base is not active.

    If no EK is called I would try replacing line 22 with



    BAS(#EX_BASE, 17)


  • I try replace line 22 with EX_BASE(17,2), don't work correct too.

    Moving base is activate, when I halt program and jog the table, robot jog too. You can see on video, robot and table move, but robot must physically stand still, and the table must rotate.


  • Then I see three posiibilities:

    - The external base measured in the table is not measured correct or the basenumber 17 is the wrong one. The base could be tilted for example. Check if the robob keeps constant position relative to moving base if jogging only the table with active cartesian reference system. $POS_ACT should stand still, $BASE_C move according to the table rotation and you should see the robot tool tip exactly describing the same arc as the table.

    - The position of the table relative to robot is not measured correctly. Check extarnal kinematic measurment. This data is stored in $config.dat MACHINE_DEF[2]. See also ROOT part of EK command.

    - RoboDk generated positions do not fit. Could be different kinematic models of RoboDksimulated table and real table on the robot. Check both models whetcher they are really the same. Do not only check link lengths but also direction of rotations.

    You could also try to use $IPO_MODE = #TCP instead #BASE. This is usually used if you a a fixed tool in space and the robot holds the workpiece. This needs also be considered in correct position generation by RoboDk. But I do not know whether RoboDk offers such a feature as $IPO_MODE at all. Basically it switches the meaning of $TOOL and $BASE and inverts $POS_ACT. From the robots point of you could think about this in the following way: The Robot no longer gets dragged along with the moving base system but pushes the moving base system away from ifself.


  • Hello Fubini

    Thank you very much for your help.

    I found what the problem was.

    In file config.dat and base orientation.


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