Accuracy

    Hello


    Some time ago I noticed differences in cutting out , I've done a simple test recently ,I wrote a program to cut a rectangle and I turned on the program with the setting Cartesian axis "A" As in Figure "1" then I moved the "A" axis 180 degrees drawing "2". The effect came out like this drawing "3" .After a few hours of checking , the suspicion fell on the wrongly calibrated robot.Why do I think so?I have checked another robot and have the same symptom,robots were calibrated the same EMT.Gentlemen, any suggestions, Maybe someone has encountered a similar problem.I am asking for advice.someone met EMT already badly calibrated the robot.

    robots it

    Kr 150 L110 krc2
    kr 210 krc2

    Problems like this are discussed already very often here.
    For the first, always comes up: answer following questions:

    - Have the robots the option absolute accuracy ?
    - Did You set the load data correct ?
    - Did You make standard calibration without the mounted tool? Or did You learn offsets? Just describe the procedure of calibrating.
    - How did You determine the tooldata?

    - What are the dimensions in picture 3?

    IMHO the EMT is not the problem. If the EMT doesn't work properly You would have much more deviations.

    Robot mastering can create that kind of errors in my case that is what happened. So I would take a manual Micrometer and do a remastering. That done should give you a reasonable accurate Robot... and would point out tours your EMT tool.

    This Load parameter is for Dynamic positioning, but it should reflect your Tool configuration, ex: B: -90 deg. ....if your spindle is at 90 deg. you know that.

    The pic shows that you have not positioned the CG correctly, it is coincident with flange face center point and the spindle is pointing straight out normal to robot flange...

    For added dynamic precision is a good idea to add the inertial values. Is that the case ?

    IF your error is static... then check your Config file in the software you are using... and in the $config.dat in the System folder I believe.

    Other than that.. maybe your RDC card ? Mine died would NOT master anymore ... so I replaced it robot was unusable.

    Edited once, last by Ceta11 (December 18, 2017 at 9:53 PM).

    I would still check TCP data, Do you have a dial gauge? If you put a dial gauge against a round tool in your spindle and you rotate the spindle around it's axis the dial should remain at 0. If it does not your tcp can use improvement.
    The reason why i would look at the tcp data is that i have worked with a robot with had been mastered incorrectly (i know because it was me who did it :uglyhammer2:) and even the slightest mastering error gave me problems when moving in a straight line. In your case there are still straight lines only in the wrong place which point's to TCP data not mastering data.

    Every problem has a solution, that isn't the problem. The problem is the solution.

    Thank you all for the answers. Tomorrow I am in place and I will try everything.leon checked the dial gauge a few days ago , I applied the sensor to the base of the axis 6 , axis 5 I set to 0 (unfortunately by hand) and I started to rotate axis 4 after turning the axis by 180 degrees made a difference of 0.3 mm .
    And so :


    1. I unscrew the tool and I'm doing calibrations Setup > Master > EMT > With load correction > First mastering , then I screw the tool and I'm doing it Setup > Master > EMT > With load correction > Teach offset.
    2. Measurement of the tool by method XYZ 4-Point ABC manually enter A0 B-90 C180
    3.Thoroughly supplementing the load data of the tool setup > tool > payload data

    If I'm wrong, please correct me.

    That sounds about right. You just have to have your SRC program set $TOOL, $ACT_TOOL, and $LOAD to the correct values before running any motions. If you use inline-form programmed points, this is as simple as selecting the tool number that you calibrated. If you are writing raw KRL, you will need to set all three variables as part of your SRC code. If you do not, then the robot will not be applying the calibration correctly.

    For testing the TCP, don't rotate an axis -- program a rotation around the tool axis. If you are using an Absolute Accuracy robot, one important fact is that the Absolute Accuracy calibration is inactive when the robot is being jogged. So any test of accuracy must be carried out by running a program.

    When I need to tune in a critically important TCP, I generally mount a dial indicator to a fixed location, then program the tool to rotate 180deg while in contact with the indicator. Then I observe the measurement, and adjust the TCP XYZ values until the deflection is minimized. This usually takes several iterations for each axis. I also need to perform "sliding" tests, where the TCP holds orientation but moves along X, Y, or Z, and use those results to tune the ABC values of the TCP.

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