can not teach tool correctly

zeev,

this is not aimed at you and it is nothing personal, i am just reaching out and trying to help. i am just using your post as an example of how not to ask question. i hope others read it too and try to proof-read their own question before posting because it is often hard to understand what people are asking about or trying to say.

example: what exactly is "kuka white robot" and how is color of the robot significant in this post? the most white Kuka robots I have seen are the old Denso arms but they used KRC2sr controller, not KRC4. providing robot details is a great step but I would rather see robot model (KR10R900 or KR210 whatever).

Quote from zeev

i teached the tool by 4 points, but i have some offset of 1-2cm.
how can i teach the tool correctly...

what does that mean? what offset is 1-2cm?

is that the error you get when you measure tool using 4-point method or - you got reasonably small error (<1mm) and you wish to manually introduce offset to that TCP, to shift TCP in space?

are you asking how to use 4-point method to measure TCP? this is described in manual and it is also in the documentation on the robot (look up what is under menu Help>Documentation)

Quote from zeev

kuka send me kuka load software, but it's not helping me.
i have the spindle and the tools that attached to it dimesions, and i prefer to enter values to it.

what does this mean? what is stopping you? Under Load menu there is numeric entry option. what do you expect this software to do? i guess you are trying to enter load data for your tool using numeric input but you don't have the correct data. is that true?

before you can enter data you need to obtain it somehow:

1. commercially available robot tools usually have load data mentioned in the data sheet. read the data sheet or call manufacturer if needed.

2. if the end of arm tooling is something that YOU have designed, you probably did not just McGuywer it with some paper clips and duct tape - you would have started by doing computer design with some 3D cad (SolidWorks, SolidEdge, ...). Such software tools have export function and will produce data that you can use on a robot directly (IF you did proper design and assigned materials etc.).

3. third option is - manual computation. This could be a good exercise for an engineering student but other than that - nobody is doing this by hand any more - unless dealing with simple shape. Spindle can be approximated as a simple shape or two (cylinder or cuboid, it is solid and mass is pretty evenly distributed with center of mass being close to center of the unit etc.). Mass can be easily determined by weighing. Outside dimensions are easily measured. Wiki and hundreds of other sites have instructions on computing inertia for simple shapes:
http://en.wikipedia.org/wiki/List_of_moments_of_inertia
This means that with very little effort and just highschool math one can get a VERY good estimate of the actual load data (if simple shape). many will frown upon mention of manual computation regardless how simple the task is. those are the ones that can't compute (didn't pay attention in school or did not have any schooling - which is pretty much the same thing).

4. fourth option is using Kuka.Load
it allows estimate of the tool load but it requires manual input (similar to third option).

5. fifth option is to use kuka.LoadDataDetermination which does all math for you. yes it is a paid option and very convenient, you pay for convenience.

6. final option is to get someone else to do this for you

Quote from zeev

but as i try, it's worst as the robot see a TCP in the air

i have no clue what this is supposed to mean. can you elaborate?

note, tool load data has NOTHING to do with tool TCP. think about it... consider simple pencil as a tool. TCP is at the tip of the pencil. center of gravity is in the center of the pencil. those are two different points representing two different things and have absolutely nothing in common, other that both happen to refer to same object.

Quote from zeev

any help will be appricate, since it's the last problem that i facing to finish the marble polish project

and this is another thing that is ... odd!

mastering robot and teaching TCP is not the last step of making a working project, it is the begin (right after robot is powered up and cell is wired). even at kuka, mastering is done on a first day of training, followed by commissioning and the rest of the week is all about programming. if you go by system integrators manual (some 15 chapters), commissioning is at the top, right after chapter that explains coordinate systems and buttons on smartPad.

if robotics is what you do, just take the training.

on the robot arm there is a silver label and information in the bottom (I think it is a last line) is MADA or robot MAchine DAta. this tells you which MADA (robot) your controller need to use. if the controller thinks it is using different robot, you have a problem. also if you have wrist extension installed/changed but nameplate and MADA in RDC was not updated.

the next question is - is there any mechanical play in the robot (specially wrist - loose belts? any collisions?)

the last question is - is your robot correctly mastered? if this is also the case, you should have no problem teaching TCP.

when teaching TCP using 4-point method, you need to make sure that 4 directions are sufficiently different. robot will complain if the directions are less than some minimum (I don't recall, think 2.5deg or so). but even if you are just above this minimum you may have a problem (though I would be surprised at error of 1-2cm).

what I normally do is use rotations A,B,C to turn tool in space, then lower it down to a reference point using translations X,Y,Z. after pressing Calibrate, I lift the tool up (Z+) then repeat the whole thing three more times and press Save. at this stage you will also have display telling you what the error is (I have not seen you mention your value). normally error here is small (fraction of a millimeter).

you may also manually edit TCP value, just need to change X,Y,Z for the tool. in fact you can measure it (using measure tape for example) from the flange. note that flange need to be in known position - send robot to it's mechanical zero position, unless it is a Quantec, that would be

PTP {A1 0, A2 -90, A3 90, A4 0, A5 0, A6 0}

in this position you know FLANGE coordinate system so you can do the mentioned measurements.

so it is all working now? congratulation

but i must admit it sounds ... unconventional. i would still recommend to get some kuka training to fill any gaps and get chance to talk face to face with someone that has answers.

I am also missing the training

I had only basic training on KRC2 some two years back.

I tried with KUKA in India and it seems like they do not have sufficient guys to train for expert programming and especially on KRC4. I am pushing my bosses for Germany but I need more luck for it.

I will try my best