Geometric operator and Inv_Pos()

    I am a little stumped by the Inv_Pos() function Kuka has. I've looked around the forum and everywhere seems to point to old integrator manuals. I'm looking for peoples sentiment on this particular problem.

    I have a robot picking from a cart, and placing on a table. I want to have a program that can be ran once and get a vector that can be used to offsets subsequent place points. So you'd run a calibration program like:

    Then the idea is at this point "NEW_CALIB_OFFSET" is the vector you seek that can be added in a different program like:


    Code
    DEF PROG_2()

...

PLACE_PT = PLACE_PT:NEW_CALIB_OFFSET

...

END

    So when you go to "PLACE_PT" it accounts for some of the inaccuracy in teaching the tool / base, some of the mechanical tooling slop and so on. This seems to work, but not quite. The values that pop out of "NEW_CALIB_OFFSET" are of magnitude <10 mm. The inaccuracy in my placement is about 2mm in X and Y.

    I don't understand how: NEW_CALIB_OFFSET = INV_POS(IDEAL_POS):XTOUCHED_UP_POS is different from NEW_CALIB_OFFSET = IDEAL_POS:XTOUCHED_UP_POS. One gives different values then the other obviously.

    I hope this ramble makes some sense. At a high level, what is the ideal use case of INV_POS()?

    Quote from work_BR

    I don't understand how: NEW_CALIB_OFFSET = INV_POS(IDEAL_POS):XTOUCHED_UP_POS is different from NEW_CALIB_OFFSET = IDEAL_POS:XTOUCHED_UP_POS. One gives different values then the other obviously.

    First is a subtraction of the two vectors, latter one is an addition of the two vectors.

    Quote from work_BR

    At a high level, what is the ideal use case of INV_POS()?

    The highest level is: use it when you need it, otherwise don't use it. :icon_mrgreen:

    There's no ideal use case, it depends on what you want to calculate. Nobody can enumerate all use cases, there exist uncountable many use cases.

    Inv pos is the reverse relation. Like your ideal_pos is a frame from base to the point. Inv_pos(ideal_pos) is the frame from the point to the base.

    Hence Inv_pos(ideal_pos):ideal_pos = $nullframe this is also true the other way around.

    Inv_pos i very powerful when trying to find the relation to something. Eg if you want to calculate the same point in another base or with another tool. Examples of this is available in the SI manual.

    There is a really good topic on this forum by MOM where alot of people pitched in. Cannot remember the topic but something along the lines of "geometric operator in depth" with really good examples and general discussion.

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