constant speed

    Hello all,

    KUKA KSS V5.6.2 with KR210


    I have an arc welding torch on the robot. In a very simple case I want to weld a direct line with two meter distance. I have used LIN motion from start to end from inline form. but the problem is, the weld is not uniform at all and it seems robot have not constant speed. I think robot start it's motion with an different speed until it reaches to my desire speed that I can see on the pendant.bat near of the line end, decreases it's motion until it reaches to zero speed. so I can't reach to an uniform weld because of robot acceleration and deceleration.

    I would appreciate if someone help me how can I get a constant speed from start to end.

    Edited once, last by Robotmei ().

    pprogram motion before and after weld that use same speed and blend them. using TRIGGER it is possible to activate/deactivate process (weld on/off)

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

    Quote from panic mode

    pprogram motion before and after weld that use same speed and blend them. using TRIGGER it is possible to activate/deactivate process (weld on/off)

    Something like this:


    P1----P2--------------------------------------------------------------P3----P4


    With the weld starting at P2 and ending at P3. Just like a car, the robot needs time and distance to accelerate and decelerate. So program P1 far enough "before" P2 that the robot has hit your target speed before arriving at P2, and pick P4 far enough "after" P3 that the robot doesn't need to start deceleration until after it's past P3. And of course, P2 and P3 need to be programmed as Continuous motions.


    TRIGGER commands at P2 and P3 will let you turn the welder on/off without physically halting the robot.

    thank you for replies,


    because I don't have enough free space before P2 and after P3 i can't get desire result.

    another problem is, when I use ordinary inline form to change state of weld output to true , it turns ON soon (probably because of advance run).

    I have never used TRIGGER command and I can see two types of this command. which one must be used in my case?

    Quote from Robotmei

    because I don't have enough free space before P2 and after P3 i can't get desire result.

    Then you have no chance, may be you can do the movement not a straight line but in an angle, so the problem isn't that hard.


    You can use both trigger commands.

    Trigger when distance=1 delay =0 sets the trigger to the next destination.

    Trigger when path=0 does the same.

    Read integrators manual.

    Quote from Robotmei

    another problem is, when I use ordinary inline form to change state of weld output to true , it turns ON soon (probably because of advance run).

    Which inline form? What Tech Package are you using for welding?


    You might need to write "raw" KRL to make this work, and not use the Inline Forms. You can look inside the ILFs and copy out the specific code you need.

    I don't use technology package, just using ordinary inline form to change the state of output to false or true. I used this with no desire result:

    $advance=0

    $OUT[1]=true

    $advance=3

    still I haven’t tried use TRIGGER command.

    Quote from Robotmei

    I don't use technology package, just using ordinary inline form

    In that case, the SYN OUT is the way to use TRIGGER commands via Inline Form.

    Quote from Robotmei

    $advance=0

    $OUT[1]=true

    $advance=3

    ...what? That makes no sense. An $OUT setting breaks the ARP regardless, there's no point to modifying $ADVANCE like that. And setting $ADVANCE to 0 is self-defeating, as it will force the robot to come to a complete stop no matter how your motions are set up.

    That has nothing to do with the content of this thread. Please be more careful of topicality in the future.


    You also provided no details as to what version of KSS you want to do this in. It matters. Please read the READ FIRST topic post.


    That said, it sounds as if you want to change the speed to 100% on the event of changing to EXT mode, but still allow the operator to change the speed while in EXT mode. This will require some coding in the SPS, creating an edge trigger:

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