Issue with UR MoveP Circle Moves

matthewd92 2016-05-24

So we are working on a silicone dispensing application where we are placing silicone inside of a cup in the corners. We have designed a tool holder that allows us to hold the pneumatic syringe at an angle so that we can reach the corner of the cup and set-up a TCP with the appropriate offsets in the Z&Y axes. On Saturday we were able to use a MoveP with 2 circle moves to circumscribe the correct circle and follow the contour of the cup. I made a new fixture which we mounted yesterday and so wanted to realign the moves with the new fixture and since then I have been having issues, see this video. I am teaching the points using TCP_3 which corresponds to this tool. I have them set the TCP in the moveP to be TCP_3, I have tried using a set command to just set the TCP before the moveP and left the TCP blank on the moveP and nothing seems to be helping....what am I doing wrong or is this a bug? The really strange part to me as you can see in the video is that when I step through the program the circle moves are done as expected and taught, its only when I press play that the tool moves to the outside of the part and traces the circle with the tool held 180 degrees rotated.

Here is a video of the process as it was running on Saturday before we had placed the cup fixture.

If you need anymore information please let me know. I have come up with a workaround that is working quite well but its not as smooth a motion. Basically I have broken the circle up into 720 arcs and am using variable waypoints to go to each of the points. At 720 arcs its pretty smooth, we were able to get it even smoother than the video by working with the accelerations, here is a video of this operating.

Etienne_Samson 2016-05-24

Hi Matt, I have seen some similar issues when using the pallet wizard, I was told this was an issue UR is working on, not sure if it's the same bug you are experiencing, I will have to verify. Can you give me your Polyscope version and Robotiq drivers version ?

matthewd92 2016-05-24

3.2.20175, have not upgraded it yet because there are bugs I'm trying to avoid with .21545. DCU-1.0.9 on the gripper.

The new script routine I worked out this morning is working very well. I am able to create a close to true circle using it and make minor adjustments. With a small tweak to the code it could be used for making ellipses as well.

Etienne_Samson 2016-05-24

Hi Matt,

Someone on the R&D told me to use a MoveJ to a fixed waypoint when you begin your program.

matthewd92 2016-05-24

I did that. It was working fine on Saturday, I adjusted the points to align to the new position and now it's not working. I'm thinking there's a bug. Also, have seen another bug which Grady Turner at Cross told me about where if you have a waypoint highlighted and then make a move using the pendant it overwrites the highlighted waypoint even if you aren't on the set screen. I've been chasing this for days as waypoints suddenly change. Pretty frustrating in a program with well over 100 fixed points

Etienne_Samson 2016-05-24

We will hope for a UR update to fix that, we are currently beta testing the next release and here are some bug-fix listed in the release notes :

Fixed issue where some of the redefined waypoints of a program retained their original position after the program had been corrected.

Fixed issue where a copied Pallet or Loop node would have the same counting variable as the original node

matthewd92 2016-05-24

I haven't had a chance to test in the beta software to see if it's been resolved or not....can only hope for a quick resolution.

Kaleb_Rodes 2016-05-25

@matthewd92 it's better off setting the TCP in the moveP command rather than using a set command before it. In addition, do not have any copied (same name) waypoints in the different moves with different TCP's. If you view the graphics tab while the program is running you can see if and when your TCP is changing.

What's the status of the program today?

matthewd92 2016-05-25

I gave up on using the circle move as it kept putting the syringe on the wrong side of the circle. I just spent the time yesterday to develop a new circle script which can also be used for ellipses.

@krodes Thanks for for the advice about the waypoints. I'm using the TCP in other moves within this program and we have another worker that has two grippers and we are constantly switching the TCP on that one. This seems to be an issue with the circle move, and not the TCP