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StefanGStefanG Posts: 7 Apprentice

Hello pros,

after teaching a feature plane on the UR (first image), when i try to "move here" the arm moves to the Origo but rotated by 180° in either wrist 0 (second Image) or wrist 2 (third Image), depending on where it starts from. What could be the reason behind this and is there a way to avoid this?

Also since updating the UR from SW 3.5.4 to  SW 3.7 I'm not able to select the axis of the feature plane created after the Update (I can't pop up the feature plane). Is anyone else having this problem?

Kind regards

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Best Answer

  • matthewd92matthewd92 Posts: 1,065 Handy
    Accepted Answer
    When you do the move here the robot is solving for the tcp location, not joint angles. They all have the same tcp position as there are two solutions for how to get to that pose. My understanding is that basically the robot is choosing the easiest path to get there, depending on where you are starting from it can get there by two paths and so will have two different joint solutions. That’s what you are seeing. It’s the same issue I have seen before with movel in programs where you have a need to put a movej waypoint before the movel to ensure you are actually in the correct joint orientation prior to executing the linear move. 

Comments

  • StefanGStefanG Posts: 7 Apprentice
    Is it possible to tell the robot what joint angels to use when going to this positions?
    Since the robot tends to crash when rotating wrist 2 while executing a program.

  • matthewd92matthewd92 Founding Pro, Tactile Sensor Beta Testers Posts: 1,065 Handy
    The easiest way is to have a movej right before you need to execute that love to get into position. Are you using the waypoint in a movel or movej?
  • StefanGStefanG Posts: 7 Apprentice
    edited September 2018
    I'm using the waypoint in a movej. When moving to the desired Position the wrist 1 (joint D) rotates by 180° causing the robot to Crash into himself (see picture below)




     
     
  • StefanGStefanG Posts: 7 Apprentice
    edited September 2018
     
  • matthewd92matthewd92 Founding Pro, Tactile Sensor Beta Testers Posts: 1,065 Handy
    I would add a point before that point that orients the robot the way that you want prior to making that move. 
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