Load Data Tool problems.

  • Goodmorning,

    I have a couple problems, maybe you can help me.

    Controller: KRC4 - 8.6.6

    Robot: KR 70 R2100

    Loaddatadetermination: 7.1.2

    1) I tryed to determinate the load data of a fully loaded tool ( product gripped in the tool ). At the end of the procedure i tryed to assign the data and i received a message saying : "Assign load data despite overload? "

    I pressed yes and it was assigned. But still i dont understand why it came out. The maximum load of the robot is 70 Kg and the data are:

    {M 61.9051704,CM {X 71.3568192,Y 28.8014107,Z 300.520,A 48.6009941,B 88.1209564,C -131.597839},J {X 4.42782593,Y 5.86921501,Z 8.46680546}}

    What could be the problem?

    Does It means that somewhere at maximum speed or extension i might have trouble? It should not be, but i have no idea.

    2) I tryed on the same robot to activate the load data verification but i can't (picture 1). Same thing for all the tools , not just the one mentioned before . I don't know what should i do. Any idea?

    Thank you In advance.

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    • Helpful

    I take it you were running the KUKA Load Determination option on the robot, correct? Did you have the tool&part mass in advance (weighed separately), and enter that manually before running LoadDet? I've found that the automatic mass determination is... well, it's not bad, but LoadDet always makes more accurate measurements if you provide it an accurate mass value before running LoadDet. It makes one less value the robot has to try to reverse-calculate from motor torques.

    I would recommend taking the mass/cg/inertia data, and run it through the KUKA Load spreadsheet tool (can be downloaded from kuka.com). That will show you a chart, similar to in Hermann's post, specific to your robot and payload, as well as how far out-of-bounds the load is, and whether the overload is static or dynamic. That won't solve your problem, but it will give you much more detail on how big the problem is.

    As a general rule, the closer you come to the robot's rated payload, the closer the CoG needs to be to the A6 flange. Inertia is the robot's limiting factor, not weight1, and inertia is the product of mass and the mass's "leverage" -- aka, the distance from the Tool 0 mounting point.

    1obviously, if you attach a 100kg payload to a 70kg robot, the robot will be overloaded even standing still -- "static" overload. But with sufficiently large CoG numbers, you can create a static overload even if the total mass is below the robot's rated payload. And when the robot starts moving, everything usually just gets worse.

  • Goodmorning guys,

    Thank you for the answers, you made it really clear. I' ll do more test to see if i will possibly have some problem. For the second problem i think i'll ask directly to kuka, it is really weird. Many thanks both of you! Have a good day.

  • Fast Update about the second problem i had (load data verification do not work) . I asked to KUKA service and In the end i just needed to delete the robot and replace it with a new one in the workvisual project. Downloaded the project all works fine now. Weird, but it works.

    That's all. Have a good day.

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