MAstering and load data trouble on my KRC4

Quote from panic mode

what controller?

do you have mastering tool?

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The robot type is : KR 10 R1100-2

The controller type is: KR C4 compact

I am not sure whether you mean the dial gauge to calibrate the axis, how can I know when should I do this calibration.

My problem is when I create tool coordinate whit '4 point method', the measurement error is about 15mm, which is much greater than 5mm. So I just set xyzabc value to create the tool, the values are basically actual. Nevertheless the tool cannot rotate around the TCP, when I change ABC manually, the tcp will left far away from its original location, but the absolut position xyz based on the tool and base donot change.

Thanks for your help in advance!

dial gauge can be used but i do not recommend it since it is cumbersome to use and results depend on user skill and patience. it is much easier to use EMD and results are always excellent.

about when to master robot: - read the user documentation. KUKA tells you that this need to be done after any repair, loss of mastering, after any collision (unless it was at low speed) and when things seem off (for example when tool calibration does not produce desired results).

it is also recommended to do it any time one starts new project or does commissioning of the cell - you do not want to spend two weeks writing programs and teaching points only to fund out that robot needs mastering.

about tool calibration. on small robots like Agilus, with pointy tool, i routinely get results as good as 0.1-0.15mm so i expect 0.5mm or better. if the tool does not have well defined tip (not pointy), this can be harder to reach so up to 1mm may be ok. At KUKA college tools are typically pointy (pencil) but the users are students and time is limited so for the sake of exercise, 1-1.5mm is acceptable too. in production, i would not like to see such poor result on smaller robots like Agilus.

to get good results you need robot that is in good working order. this includes:

1. correct robot MADA. without this you will never get TCP to work.
2. robot mechanically ok (no slipping or damaged writs belts etc.)
3. robot is mounted correctly... must be on a firm base, using mounting kit.
4. robot tool is mounted correctly ... firmly attached and using dowel pin.
5. robot is correctly mastered (preferably using EMD, but if that is not available dial gauge can be used too)

those are some of the steps that are part of commissioning procedure. unfortunately many robots are never commissioned correctly. users often skip all they can just to get robot to move, then they pat themselves on the back and call it job done. taking KUKA training courses is highly recommended but - it is not enough. courses only teach you selection of cherry picked topics. one must still read the documentation for broader understanding and things not covered in training.

Quote from panic mode

dial gauge can be used but i do not recommend it since it is cumbersome to use and results depend on user skill and patience. it is much easier to use EMD and results are always excellent.

about when to master robot: - read the user documentation. KUKA tells you that this need to be done after any repair, loss of mastering, after any collision (unless it was at low speed) and when things seem off (for example when tool calibration does not produce desired results).

it is also recommended to do it any time one starts new project or does commissioning of the cell - you do not want to spend two weeks writing programs and teaching points only to fund out that robot needs mastering.

about tool calibration. on small robots like Agilus, with pointy tool, i routinely get results as good as 0.1-0.15mm so i expect 0.5mm or better. if the tool does not have well defined tip (not pointy), this can be harder to reach so up to 1mm may be ok. At KUKA college tools are typically pointy (pencil) but the users are students and time is limited so for the sake of exercise, 1-1.5mm is acceptable too. in production, i would not like to see such poor result on smaller robots like Agilus.

to get good results you need robot that is in good working order. this includes:

1. correct robot MADA. without this you will never get TCP to work.
2. robot mechanically ok (no slipping or damaged writs belts etc.)
3. robot is mounted correctly... must be on a firm base, using mounting kit.
4. robot tool is mounted correctly ... firmly attached and using dowel pin.
5. robot is correctly mastered (preferably using EMD, but if that is not available dial gauge can be used too)

those are some of the steps that are part of commissioning procedure. unfortunately many robots are never commissioned correctly. users often skip all they can just to get robot to move, then they pat themselves on the back and call it job done. taking KUKA training courses is highly recommended but - it is not enough. courses only teach you selection of cherry picked topics. one must still read the documentation for broader understanding and things not covered in training.

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Hi, Panic

Thanks for your patient response.

I will re-master my robot by using EMD as you mentioned. Because I am a newer here, I don't understand the first point clearly. What should be checked about MADA? Do you mean the file '$machine.dat' and '$robcor.dat', there are many variables in this two files.

there are two sets of MADA (Machine Data)

robot MADA is in KRC:\R1\Mada. ($machine.dat + $robcor.dat)
Controller MADA is in KRC:\STEU\Mada ("Steuerung" = Controller)

when you connect different robot to KRC, MADA for the robot need to be replaced. Robot MADA contains everything that describes that arm including length of joints, gear ratios of each axis, direction of each axis etc. if any value is changed, robot may not work correctly. for example wrong gear ratio or joint length will produce what you are seeing.

so when one is told to check MADA, it means comparing the entire robot MADA with clean one and try to find any difference that may be significant. some changes are normal, for example if an external axis is added. but anything related to six robot axis should match perfectly.