Joint position in world coordinates

mwescott NIAR/Wichita State University
I have a Yumi that is really close to a light curtain.  Sometimes the elbow will go into the light curtain shutting everything down.  Is there any way to get the joint positions in x,y,z so I can mute the light curtain when a joint is near it?  I am aware of world zones and this robot does have that option but I have not found a way to use it for this.  I need to know more than TCP position in world coordinates.


  • Tompanhuhu
    Tompanhuhu Sweden
    Sounds like a bad solution to the problem. 
    Systemintegrator - Web / C# / Rapid / Robotstudio

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  • graemepaulin
    graemepaulin New Zealand mod
    edited January 12
    Do you have the world zones manual?
    It has good examples of how to set up a zone which sets an output when reached.

    Why do you need a light curtain in the fist place as the Yumi is a collaborative robot?
    Also if the robot and light curtain is that close there is not enough stopping distance for the light curtain to be effective?
    Post edited by graemepaulin on
  • mwescott
    mwescott NIAR/Wichita State University
    I am aware of that.  I am not protecting people from the Yumi.  We also have a soldering robot and a cutter in the cell.  The light curtain is muted until either of them activate.  However, I can't release the mute as long as the right arm is in the light curtain.  I need a method to determine if any part of the arm is past a plane to the right of the robot around 400 mm.  I believe safezones from the SafeMove can do this but it does not have this option. World zones will only let you know if the TCP is in an area.  The only joint positions it gives is angles.  Are there any other options I am not aware of to solve this?
  • graemepaulin
    graemepaulin New Zealand mod

    Thanks for the explanation.

    Would the below do the job when combined with WZDOSet to make an output when inside\outside the limits?

  • lemster68
    lemster68 United States ✭✭✭
    That is what I was about to suggest.  It would be up to you to determine the combinations of joint angles that would place the part of the arm inside that light curtain.  When dealing with safety it is standard to have a signal stay high when conditions are safe, go low when not.  Why?  If the Yumi was in the not safe area and powered down, then its output will still be off.  A fail safe measure.
    Lee Justice
  • mwescott
    mwescott NIAR/Wichita State University
    I have thought of that.  I am not sure how I would determine all the angles of each joint that would put it in the light curtain though.  I may have another solution I am going to try.  All my current world zones I believe the robot is out of the light curtain.  I will just check if the robot is in any of those before muting.  I can setup a cross connection tied to all those zone outputs and add it to the cross connection that activates the muting.  I will then activate the interrupt that pauses any motion while the muting is off and robot is not in a world zone.