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Advance pointer trick with a WHILE LOOP KUKA KRC4 8.x

  • Hello all,

    I would like to create a small delay of my advance pointer but still want to avoid the robot to stop because of that (when this delay is short enough to permit it).
    I will receive my positions from an external software. At some point in the robot program, I will have to wait about 200ms before I get the next calculated buffer/points....


    So in "college" style, my code would look like this :


    START PROGRAM EXECUTION

    (...)

    $ADVANCE = 5 ;

    SPTP point1 C_DIS ; ETA ~ + 300ms (need aprox 300ms before this point is being approched)

    SPTP point2 C_DIS ; ETA ~ + 300ms

    SPTP point3 C_DIS ; ETA ~ + 300ms


    WHILE NextPointsReady == FALSE

    DoNothing() ;;;;; For this example, let's pretend NextPointsReady will turn to TRUE (by SPS) after 200ms from the moment my advance pointer entered this loop.

    ENDWHILE


    SPTP point4 C_DIS ; ETA ~ + 300ms .

    SPTP point5 C_DIS ; ETA ~ + 300ms .

    SPTP point6 C_DIS ; ETA ~ + 300ms .

    (...)


    So you understand the idea is to use a WHILE statement to be able to WAIT_FOR a condition without stopping my advance between point 3&4.

    I cannot use CONTINUE + WAIT_FOR (instead of WHILE) because the point 4 , 5, 6 cannot be calculated before the condition NextPointsReady is valid.


    Questions:

    1) Does the above example has any chance to run smoothed all the way and without visible delay during/before/after?

    2) Would it still work exactly the same if I have $ADVANCE= 3 (I assume yes)?

    3) Would it still work exactly the same if I have $ADVANCE= 2 (I assume in best case will depend on the CDIS value compared to the distance to travel, worst case is not smoothing between 3&4)?

    4) Let's assume that my WHILE loop never stops and $Advance=5 : will the robot go smoothly up to the point3 and then stop? (I believe yes)


    I do not yet have a robot to test this, but this is kind of a key point for my thought.


    I have experience with PLC and software programming but not much yet with Robots so I hope I was clear enough.

    Edited 2 times, last by ComaWhite ().

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  • The advance pointer will (or will at least try to) send whatever coordinates it sees to motion planner; and once motion planner does it's job, changing the values of a point will not effect the already planned motion. Which means that at the very least controller must have point 4 coordinates before the TCP makes it to point 2.


    Trapping advance pointer in a loop should work if you won't actually call any functions.

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