Nonsensical TCP behavior

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  • Reply to Hermann :


    Well I'm standing on the X axis of the robot, so when I rotate tool A +90, the tool is on my right, and when I rotate -90, it's on my left. Get it ?


    Forget the numeric data if you don't need it.

    I'd just like to understand how it is even POSSIBLE that the point of my tool shifts in that direction.

  • looking at misalignments in the picture i would say you are lucky to get 0.78mm error.

    also your process and presented data are still not very clear to me. you still did not do as i asked.


    no offense but this makes it difficult to help you as you keep posting things that you find interesting. but this does not help much. there is a reason people ask for help so try reading responses and answering questions.


    for example:


    1. did not show tool as robot is in cannon position. this is a fundamental step needed to ensure correct mounting and something to something needed to verify and interpret your tool data.

    2. did not provide anything for scale reference and this is needed to verify and interpret your tool data.

    3. did not provide actual tool frame data

    4. did not provide tool number. one of screenshots did show tool 15 but there was no confirmation in form of screenshot that you selected correct tool coordinate system and that tool.

    etc.



    so if you need help, try providing info we can relate to. this is what i would do and expect from others when trying to verify tool frame:

    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

  • It SAYS move to a negative Y and SHOWS a positive Y ...

    No, it says: move, so that the origin point has a negative coordinate in the xy plane.

    This will happen when you move into the positive y direction, the origin point then goes to negative values. A bit of misleading instructions.

    But this example shows that it is not that impossible to make erratic assumptions while not reading advices complete and follow them exactly.

  • Nope. Sorry to be a stickler here, but that's not what it says.

    It says "Move the tool so that the reference point in the XY plane has a negative Y

    value."

    Sorry YOU are right, had a wrong remembering. Looked into the german version of the manual (which will be the original). There they say "positive" value. The translator made the error =O

  • that looks good and matches your tool data

    so steps 1,2,3,4 are done. now to verification as described in 5, 6. need to see the tool coordinate system selected, tool 15 selected and try moving tool again without leaning on space mouse.

    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

  • Holy cow... I had it wrong from the beginning.

    I SHOULD HAVE BEEN USING A FORK !!!


    OK, I see what you mean. You want to check if I'm a total idiot, and you are right.

    So back to fiddling the pointy thing around...


    well i was testing my ... artistic bone.


    and good... that means progress.


    It is rather common that people asking for help, choose to give their own opinion or interpretation of what they have done or seen, rather than posting proof of what they are doing or observing. and those are very different things, specially whey are not sure what to do or look for. i would always much rather see actual data and decide for myself if the performed task is meaningful and if observations make sense. but this tends to be one thing that is hard to get across...


    how many times have you seen posts with "i already checked X11 wiring" or "i checked Fieldbus settings and everything is ok". yeah right... both examples show very clearly an attempt to share completely useless piece of information. that only muddies the water and it is counterproductive...


    so occasional kick in the tenders to reorient them and help them focus may be needed ;)

    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

  • so occasional kick in the tenders to reorient them and help them focus may be needed ;)

    I agree. Actually, your nit-picking reminded me of Werner's video that I "though" I had watched carefully.

    In fact, (what I had overlooked) he insists on not changing the angles too much between measurements.

    After the first measurement is done, he rotates axis 4 slightly more than 7° and moves the dummy tool tip back to the ref. point in carthesian.

    He does the same with axis 5 for the third measurement, and again with axis 6 for the 4th. measurement.


    I followed his advice and also, each time took close-up pictures of my tip, then zooming on the picture to finely adjust X, Y and Z.


    Guess what ? I got an error of just 0.115 !!!

  • your tool measurement is fine. the question is do you still see robot moving in wrong direction when trying to rotate about tcp. if so, what exactly is selected and how it is tested.

    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

  • then you have something else going on, either it is something really corrupt in your KSS or you are using wrong coordinate system or IPO mode etc.

    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

  • sigh... my words are ignored again. HMI screenshot is cropped and does not show used coordinate system.


    but at least it is clear that correct tool is selected, also TCP is at same point and XYZ values are matching, orientation matches tool data too. so everything looks fine.


    earlier in your first post you reported that rotating about this tool Z axis using jog keys (A+/A-), tool was not really rotating as expected but rather moving along the tool Z axis.


    can you confirm that this behavior is not what you are seeing now?


    can you conduct checks 5 and 6 in post 63?

    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

  • earlier in your first post you reported that rotating about this tool Z axis using jog keys (A+/A-), tool was not really rotating as expected but rather moving along the tool Z axis.

    The rotation is exactly as expected. What is strange is the translation of the dummy tool point ALONG the tool "A" axis.

    Anyways, it is evident that the XYZ are completely wrong.

    I just don't understand how it can be THAT bad.

  • It goes back to my one of the first posts in this thread.

    As I rotate around tool "A" (tool "Z" ) axis, the pointy end shifts in an un-expected direction.


    Consider the "real" point in space described by my current tool XYZ.

    As I rotate around tool "A", the pointy end should move in a plane normal to the "A" ("Z") axis, but certainly not ALONG that axis.


    It's just geometry basics.


    The fact it moves the way it does is what makes me call it "Nonsensical".

    I can't even use this deviation to correct my values because it is not "false" , it is just awkward.

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