• Hello,

    Could you please help me.

    I am testing on a kuka krc4 robot.

    I tested several configurations to pass the singularities like $ CP_VEL_TYPE or $ ORI_TYPE = #JOINT or $ SINGUL_POS [].

    For these 3 variables, I can tell you the difference in behavior.

    But with $ SINGUL_STRATEGY I can't seem to see the difference.

    If in Option.dat I put 1 or 0, it doesn't change anything.

    My program is very simple:

    PTP XP1

    LIN XP2

    from XP1 to XP2, I go through a singularity $ SINGUL_DIST [3] at 0.2.

    but the robot does not apply orientation to pass the singularity.

    Do I go about it badly to highlight it?:face_with_rolling_eyes::face_with_rolling_eyes:

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  • KRC4 is not a robot, it is a robot controller. controller or robot type have little or nothing to do with programming. for this, KSS version would be more important.

    Alpha5 can happen anywhere in working envelope. CP motions are affected by singularity. one way out is to not use CP motion (LIN,CIRC) ... use PTP if possible (or things that sound like PTP).

    also read variable manual, it tells you what option #JOINT means for orientation - it is an interpolation based on a rigid linear transform.

    to get around singularity you want flexibility, and that can be obtained through a non-linear transform, hence you should try #VAR. it is same as "WRIST_PTP" in Inline forms.

    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

  • Hello, thank you very much for your feedback, I am well aware that the singul_strategy orientation can be dangerous but I would still like to try it out. the variable is available in option.dat and I only see this to activate it. If you have any leads ...? thank you in advance

  • Thank you "Panic mode", I am very happy that you answer me. I have seen many of your posts. Thank you for sharing your great skills. For my problem .... I am in Kss 8.6. I know the peculiarities of singularity but what I'm trying here is to evaluate the efficiency of the singul_strategy variable compared to ori_type. Even though I change the value of the singul_strategy variable, I don't see any change. Normally when passing through the alpha5 singularity zone, I will see an adaptation of the orientation of the TCP to pass the singularity. NO? thank you

  • No. Talk to Kuka. I remember you had to enter a special value like 45367 somewhere. But I do not remember either the value nor the variable you had to use.

    Anyway KUKA did not officially release this feature for no reason. What is the goal of your comparison then? What is the underlying problem you need to solve?


  • KIDY

    why do you want to go thru alpha 5 (A5 = 0.0°)

    Mathematically it is not possible to calculate the values for A4 and A6 with A5 equal 0 (reason(sin(0°) = 0 and you may multiply any number with 0.0 and the result will be 0.0 => values for A4 and A6 would be 0°)

    As Fubini mentioned there is a way to use your "1". You did not activate this feature and therefore you cannot see any difference .

    I which mode did you run the program (T1/2, AUT)

  • Thank you all for your support,

    MOM, to answer your question, I tested in T1 and AUT.

    To be clearer in my problem, I have made simulation videos for you.

    These videos are in T1 but the behavior is the same in AUT. I tested.

    On the first video, we can see the trajectory that passes through the singularity. All variables are at default values. In T1 axis 4 turns 180 ° but in AUT there is no overspeed fault.

    On the second video, I pass $ ORI_TYPE = #JOINT. We can see that the robot passes the singularity with a big reorientation of the tool. The trajectory is the same in AUT.

    On the third video, I reset $ ORI_TYPE = # CONSTANT and I set the variable $ SINGUL_STRATEGY to 1. In T1 axis 4 turns 180] but in AUT we don't have the overspeed fault. Why does the robot not adopt another strategy since SINGUL_STRATEGY = 1

    Thanks everyone.


    2: https://drive.google.com/file/…g3y4K-_G/view?usp=sharing

    3: https://drive.google.com/file/…dotKUOli/view?usp=sharing

  • Its perfectly clear that the version with $SINGUL_STRATEGY is not working. I have already told you it is blocked by KUKA due to unwanted behavior and henceforth not officially supported out of the box. You need to contact KUKA to get the secret activation method I mentioned earlier.

    I do not get the problem people always have with contacting KUKA in the first place. Is it so difficult to pick up the phone and call them or send an E-mail?

    Btw. your answer does not answer my question why you want to do all this tests. Every of the strategies has its advantages and disadvantages that might present themselves differently based on a specific program or task.

    So once again: what do you try to achieve apart of having fun with the robot controller?

    For example a possible answer would be: I am an ABB field engineer and want to benchmark KUKA systems :smiling_face:

    What are your requirements concerning singularities: E.g. I need to pass with or without velocity reduction?

    Also the best strategy always is to avoid singularities all together by a reasonable hardware setup considering a suitable tool mount.

    Finally: Your videos do not work for me. I never use platforms where you have to register first to see content.


  • Quote

    I do not get the problem people always have with contacting KUKA in the first place.

    Well actually I know a reason. I few years back I heard only about 20% of KUKA software packages is used with a valid license. Do not know for sure this figure is correct but I would not be surprised.

  • Hello Fubini, Thank you for your answer.

    You will notice that this is my first post on this forum. "What a welcome!"

    If I posted, it is because I have already exhausted the official methods.

    I have no difficulty in taking my phone, be reassured.

    What could a forum do well if the manufacturer still had the opportunity to respond.

    Also, to answer you, I am indeed between 2 integrations of machines and I therefore have a little time to do tests on the different solutions facing the singularity at kuka.

    I thank you for the time you took to answer me.

    I will find.........

    Ps: my licence is valid.

    Ps Ps: If we can philosophize on this site ..... Me what I do not understand .... How there are people who respond on sites to prejudge and say nothing. Maybe to get rid of it for free. More tolerance and less prejudice will do a lot of good for some in this world.

  • Good morning,

    if you take the remark on licensing as a personal offense in your direction I apologize. It was not ment this way. More of a general remark.

    Also my remarks usually are not intended to criticize in any way only to get better understanding on the underlying problems to be able to give better advice.


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