Standard Vs WristPTP

    Hello
    Could anyone help me with clarifying the difference between Standard and WristPTP in LIN motion? unfortunately I've never had the opportunity to try difference with KRC4 but I've tried it a little with KRC2 (KSS5.5) in adhesive application on glass, they had some difference in handling the glue profile in curve of glass but eventually I can't find the exact difference?
    sharing any experience especially in glazing and adhesive application could be great
    thank you so much

    Basically your cartesian coordinates X,Y,Z are still followed exactly with mode WristPTP but in orientation control you might see differences caused by running the hand axes A4, A5 and A6 in PTP-mode. Hence you still reach your programed cartesion orientation A,B,C but the orientation path from the start to the desired orientation is different than in standard orientation mode. The movement path of the hand axes is more like if you had programed a PTP motion command. Main advantage of WristPTP mode is you no longer have the A5 = 0 singularity due to axis specific movement of the hand axes.


    Fubini

    Edited once, last by Fubini ().

    Dear Fubini
    Thank you for your help. It is still unclear to me what is the exact difference between orientation changes for Standard vs wristPTP. What I infer from your reply is that the way that orientation changes in WristPTP is not deterministic or predictable. Also as noted by Kuka in my attachment, wristPTP uses linear transportation. Does it mean that 4-6 axis angles change linearly along the path and if it is so, in which way the standard method differs?

    [size=2]actually the term was "linear transformation" (not transportation).[/size]
    [size=2]of course details are under wrap as with anything proprietary.[/size]


    [size=2]this is how i look at it. if there is no singularity, both orientations look much the same.[/size]


    [size=2]With WristPTP robot just goes through singularities instead of complaining about them. [/size]
    [size=2]When there is a singularity, wrist orientation changes automatically to avoid A5 singularity. [/size]
    [size=2]This means speed can change too, also tool direction may also change slightly if required.[/size]

    Quote from Amir Elmi


    Thank you for your brilliant explanation
    Can we say generally, at first we should use Standard but if robot passes through a wrist axis singularity we should use WristPTP.


    Not really, no. Using WristPTP motion may get you past the singularity, but will have unpredictable affects on the speed and orientation while the wrist axes are near the singularity. For some operations, this might be tolerable. But for others (paint, arc welding, laser cutting) these side effects would be completely intolerable. You can also create new potential collision issues.


    WristPTP is, essentially, a last-ditch workaround that can be used only when you must have interpolated motion, cannot fix the singularity issue in a proper fashion, and can tolerate all the side effects of using WristPTP.

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