Writing a script on pendant

ctiger 2019-04-08

I would like to know how does the UR 10 or UR in general read the script coding? Does the UR execute the script and perform its operation and goes to the next line?

The problem I am facing with palletizing is that every time the UR pick up the parts from the CNC lathe, the end effector needs to orientate the part in 180° and -180° (my reference point might be wrong here, just giving an example) and placed in a box. It is shown below that I need to achieve that placement.

I read the script function and I could not find anything regarding about the palletizing function, is the palletization function hard coded?

If palletization function is hard coded, would that mean before the palletization line, I would have a script which orientate the end effector and go down to the next program line into palletization mode? Would this behavior be accepted in UR? I have search up script command and read up the script manual, the manual did not explain how the function return a value or how does the information pass down to the next line.

Any advice are greatly appreciated.

Thanks

ctiger 2019-04-11

Ok by reading these 2 links https://s3-eu-west-1.amazonaws.com/ur-support-site/50482/scriptManual.pdf and https://s3-eu-west-1.amazonaws.com/ur-support-site/29983/Script%20command%20Examples.pdf somehow get a jizz of it, how do I change the pallet approach orientation when my script is called? I put my script above approach line and after it execute the script line, it goes back to the original orientation. Is switch case function within the Polyscope GUI that can be used to alter the orientation?

Nicholas_Francoeur 2019-04-11

@ctiger, yes every line in the script will be executed and move on with the next line of the program.

In your case, I would probably simply use a count and a if statement for the approach sequence. Every odd numbers would be placed with 0deg orientation and every even numbers would be placed with 180deg orientation.

Can you share you program so that we can have a look at what you're trying to achieve?

ctiger 2019-04-11

   Robot Program
     MoveJ
       home
     MoveL
       Waypoint_15
       Waypoint_16
       Waypoint_17
     MoveJ
       Waypoint_1
       Gripper Close (1)
     Set DO[0]=On
     Set DO[0]=Off
     MoveL
       Waypoint_2
     MoveL
       Waypoint_3
     MoveJ
       Waypoint_4
       Waypoint_12
       Waypoint_13
     MoveL
       Pressing_button
       Release_button
     MoveJ
       Waypoint_7
       Waypoint_8
       Waypoint_9
       Waypoint_10
       Waypoint_11
       Waypoint_14
     Pallet
       Pattern: Square
         Corner1_1
         Corner2_1
         Corner3_1
         Corner4_1
       PalletSequence
         If (cnt_1%2) == 0
             Approach_1
             PatternPoint_1
        Gripper Move50%
             Exit_1
         Else(cnt_1%2) == 0
             Approach_2
             PatternPoint_1
        Gripper Move50%
             Exit_1
     MoveJ
       Waypoint_18
       Waypoint_19

The last part palletsequence, I change both approach to 0deg and 180deg. I also changed the patternpoint but when it does either odd counter or even counter on the approach line the wrist3 will rotate and goes to the next line patternpoint and it rotate back. Do I have to rename the function so that it will rotate differently?

I also notice that it will not move to the next column or not executing the PalletSequence.

Thank you @Nicholas_Francoeur

Any suggestion or advice are greatly app

I will keep trying different position to observe the movement.

Nicholas_Francoeur 2019-04-11

@ctiger, would you share the .urp file?

ctiger 2019-04-11

I have edited the approach position and rename patternpoint.

Thanks in advance.

Nicholas_Francoeur 2019-04-12

@ctiger, you should keep only one approach point. Make sure that it is the anchor point of the pallet wizard. You then insert your if statement right afterwards.

In your case, you would have the following:

ctiger 2019-04-12

   Robot Program
     MoveJ
       home
     MoveL
       Waypoint_15
       Waypoint_16
       Waypoint_17
     MoveJ
       Waypoint_1
       Gripper Close (1)
     Set DO[0]=On
     Set DO[0]=Off
     MoveL
       Waypoint_2
     MoveL
       Waypoint_3
     MoveJ
       Waypoint_4
       Waypoint_12
       Waypoint_13
     MoveL
       Pressing_button
       Release_button
     MoveJ
       Waypoint_7
       Waypoint_8
       Waypoint_9
       Waypoint_10
       Waypoint_11
       Waypoint_14
     Pallet
       Pattern: Square
         Corner1_1
         Corner2_1
         Corner3_1
         Corner4_1
       PalletSequence
         If (cnt_1%2) == 0
             Approach_1
             PatternPoint_1
        Gripper Move50%
             Exit_1
         Else(cnt_1%2) == 0
             Approach_2
             PatternPoint_1
        Gripper Move50%
             Exit_1
     MoveJ
       Waypoint_18
       Waypoint_19

The last part palletsequence, I change both approach to 0deg and 180deg. I also changed the patternpoint but when it does either odd counter or even counter on the approach line the wrist3 will rotate and goes to the next line patternpoint and it rotate back. Do I have to rename the function so that it will rotate differently?

I also notice that it will not move to the next column or not executing the PalletSequence.

Thank you @Nicholas_Francoeur

Any suggestion or advice are greatly appreciated.

I will keep trying different position to observe the movement.

ctiger 2019-04-15

@Nicholas_Francoeur thank you for the modified program. These are the behavior I have noticed after changing the program. I have changed the anchor point to the approach point, when I start the cycle, the odd will change wrist_3 to 180deg, and even is 0. But when it comes to the patternpoint for both odd and even counter, it keeps going to the first corner and not the next column. I can't seem to get the approach to place to the next column or row.

Thanks in advance.

Nicholas_Francoeur 2019-04-15

Hello @ctiger,

Looks like the pallet wizard has changed a bit since Polyscope 3.9. I have redone the program sequence and did put the If statement out of the pallet wizard in the program tree. Everything works as expected. Find the program attached. Note that I used some relative waypoints inside the if statement.

ctiger 2019-04-15

Hi @Nicholas_Francoeur,

Not sure what I have done wrong. I bring out the if statement from the palletsequence tree, and tried running the program, I still having the issue of not going into the next column under the approach line. After the approach line it goes back to corner 1 instead of working towards corner 2. I am currently using PolyScope 5.1, would that be the issue? I have tried running the pallet_180deg.urp program and the behavior is the same as what I am facing.

Thanks in advance.

Nicholas_Francoeur 2019-04-15

@ctiger, Can you try reteaching you corner waypoints? Have them above your wooden box. Then have the approach point below them.

ctiger 2019-04-15

Hi @Nicholas_Francoeur ,

I made the mistake of not changing the move to relative waypoints, I will try again.

Thank you

Nicholas_Francoeur 2019-04-16

@ctiger, let us know how it goes!

ctiger 2019-04-16

Hi @Nicholas_Francoeur,

Relative waypoint behavior is something I do not comprehend. I tried setting from corner 1 and to approach, during the operation for 'even' it works fine. But when comes to 'odd' operation it will continue as 'even' orientation, even though I change wrist 3 to 180deg. I noticed when the UR is doing palletization towards corner 2, wrist 3 tend to turn slightly before patternpoint.

Not sure why the wrist 3 turn slightly towards corner 2 but I suspect is due to the referencing to the corner.

Nicholas_Francoeur 2019-04-17

@ctiger, have a look at the UR software manual here.

A relative waypoint would be:

A waypoint with the position given relative to the robot arm’s previous position, such as “two centimeters to the left”. The relative position is defined as the difference between the two given positions (left to right). Note: repeated relative positions can move the robot arm out of its workspace. The distance here is the Cartesian distance between the TCP in the two positions. The angle states how much the TCP orientation changes between the two positions. More precisely, the length of the rotation vector describing the change in orientation.

In your case for the IF statement:

If count%2≟0

MoveJ

Waypoint_1 - Relative waypoint with start point at your pallet approach point and end point which would be your 0 degree placed pose

Gripper Move10mm (1)

Wait: 1.0

Exit_1 - Relative waypoint with start point at 0 degree placed pose and end point which would be 100mm for example

Else

MoveJ

Waypoint_2 - Relative waypoint with start point at your pallet approach point and end point which would be your 180 degree placed pose

Gripper Move10mm (1)

Wait: 1.0

Exit_2 - Relative waypoint with start point at 180 degree placed pose and end point which would be 100mm for example

Hope that helps!

ctiger 2019-04-22

Hi @Nicholas_Francoeur,

Thank you for the example, I tried setting the relative waypoint which you have mentioned start point same as the approach. The 180 degree for the waypoint_2 will rotate and go downward at the same time, so I added another waypoint, waypoint for the wrist_3 to rotate and the other waypoint to go downward.

It works fine until it goes to sixth iteration, I noticed that before arriving at approach point, wrist_3 will rotate slightly and the 180 degree is offset.

How do I stop the rotation for wrist_3 while moving towards the approach point?

Thanks in advance.

ctiger 2019-04-22

I got it, it is due to the interpolation of the corners which causes wrist_3 to rotate slight towards approach point.

Once again thank you @Nicholas_Francoeur