KUKA collision detect/torque monitoring

    KRC4


    Say for some reason, the robot does not pick up a part and tries to load the next or the part its loading is over sized and doesn't fit into the fixture.....I am wondering if the robot can stop fast enough without a warning alarm to allow me to remotely 'stop the robot and home it' using the external HMI at the operators station.(the HMI already functions correctly with this set-up, as we are removing the teach pendant during production) All I am worried about now is somehow getting the robot to stop in a manner that the operator can just do an error acknowledge from the HMI and home it and manually clear this "trouble part".



    I would like to monitor the torque somehow and stop the robot before it gets a torque warning (which requires me to go into the SmartPad in T1 and confirm all to reset alarms and then go back into AUT EXT to resume my program).


    First robot integration, may be something simple or just a NO.


    P.S. I cannot slow the robot down when entering fixture as this will drastically impact cycle time.



    TIA

    using torque to detect "bad" situations?


    why don't you go to a car dealership and ask them to sell you a car that can be parked by driving into a wall or closed garage door but without any damage. and demand that engine need to sense the condition and stop fast enough so there are no dents or scratches.

    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

    Haha 1

    I completely understand what you are saying. These are my thoughts also. Just doing what I was asked to do. I just needed to get someone else to say it. :thumbs_up:

    if you are doing that just based on torque, make sure to reduce speed and motor current limits during "contact" phase. SI manual shows examples.


    but i would recommend to stick with what things are meant to do.


    need to move? get "mover"... (actuator or kinematic)

    need to sense? get sensor...


    this allows detection to be done safely, quickly and contact free.

    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

    Technically one could make a car auto-park itself by bumping into things. But unless that "bumper car" process was carried out at very low speeds, there's going to be a lot of damage in the process. The root issue is inertia, and stopping distance. Like a car, a robot can stop instantly... if it's moving at something like 1mm/sec. As the speed and payload go up, so does the stopping distance. A fully-loaded KR60, for example, moving at 2m/s, could easily take 100mm to stop even for a 0-category safety stop (basically, kill power and slam brakes on). There's the length of time it takes for the robot to detect the torque, then issue a stop command, then the physical deceleration to a complete stop.


    Bottom line: Collision Detection only reacts after a collision has started. It can reduce damage from a collision, but it's ability to do this drops off drastically as the speed increases.


    There's also the "numbness" factor. A KR60, rated to carry a 60kg payload at high speeds, wouldn't even notice a 1kg external force, most of the time. Bigger robots are even more "numb" to small forces. This is one of the ways that robots can be fatally dangerous -- people are "squishy" enough that a mid- or high-payload robot could easily apply lethal crushing force, even at low speeds, before the robot ever notices that it's hit something.


    (if you've ever been trapped between a wall/fence, and a horse that's decided to lean on you, you get the idea. Except robots are even dumber than horses)

    Thank You both for your very helpful responses. It looks like we will be going with a different method of sensing a part in the way. (probably vision)

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