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TCP problem UR3 robots
#1
Hello!


I got into a problem with a UR3 robot. To summarize: if I read the joint position for the particular TCP position of the real UR3 robot and them use this joint values in a RoboDK environment and compare the TCP value of the simulation and real robot - we get some deviation. TCP positions deviate from 1 to 2 mm. What could be the problem? I tried at several different robot positions, but we always get some deviation in the TCP position.

Thanks for the help.

Best regards.
Mitja
#2
Hi Mitja,

Each UR robot kinematics is unique. You should follow the procedure described here to load the controller kinematics in RoboDK:
https://robodk.com/doc/en/Robots-Univers...Kinematics

Albert
#3
Hello!

Thanks for that information, now it is clear to me.

Maybe one more question. The following steps are required (link: https://robodk.com/doc/en/Robots-Univers...Kinematics):

1. Open your robot in RoboDK. You'll find your UR robot in the RoboDK library. You can also use a UR robot available in one of your existing RoboDK stations.

2. Select Tools-Run Script

3. Select UR_LoadControllerKinematics

4. Select the URP file extracted from the robot controller.

But under the tab 'Tools' I have no options Run Script. Is there anything else I need to do to make this possible? I also don't have the options: Robot Parameters -> Use Controller Kinematics ...

Thanks for the help and best regards.
Mitja
#4
Hi Mitja,

Can you make sure that you are using the latest version of RoboDK.
The "Run Script" option is something we added a few months back.

Jeremy
#5
Hello!

Thank you very much for your help!

I updated the version to the latest and it works.

I just want to make sure exactly which URP file is to be obtained from a real controller? Does this URP file have any specific name, and where can I find it on a real controller?

Thanks and best regards.

Mitja
#6
You simply create a new program directly on the teach pendant of your UR robot.
I generally add one MoveJ to the program.
You can then save it on a USB stick and bring it to your computer.

No specific name required.
Jeremy
#7
Hello!

I created a URP file (I added a moveJ command motion), but when importing a URP file into the RoboDK tool tells I get the following:

Kinematics information not found in the URP file provided.
Did you select a URP file generated from a real UR controller.

Robots Program:
def testc():
set_analog_inputrange(0, 0)
set_analog_inputrange(1, 0)
set_analog_inputrange(2, 1)
set_analog_inputrange(3, 0)
set_analog_outputdomain(0, 0)
set_analog_outputdomain(1, 0)
set_tool_voltage(24)
set_runstate_outputs([])
set_payload(0.0)
set_gravity([0.0, 0.0, 9.82])
while (True):
$ 1 "Robot Program"
$ 2 "MoveJ"
$ 3 "Waypoint_1"
movej([1.5582780656525672, -1.2129663415552285, -1.4723813413700129, -1.85480444469633, 1.5921288224410384, -0.6577450756658365], a=1.3962634015954636, v=1.0471975511965976)
$ 4 "Waypoint_2"
movej([2.8270797033930397, -1.166960755703696, -1.7465970572876306, -1.8233039574680792, 1.5783713037600406, -0.6577126703216907], a=1.3962634015954636, v=1.0471975511965976)
end
end


I created the URP file on a real robot controller and then uploaded it to a PC. What could be wrong - we are using the UR5-CB series robot.

Thanks and best regards.

Mitja
#8
Hi Mitja,
Can you provide the URP file?
Albert
#9
Hello!

The URP file is in the attachment.

Best regards.

Mitja


Attached Files
.urp   test_calibration.urp (Size: 2.2 KB / Downloads: 75)
#10
Hi Mitja,

It looks like this is a new format we were not aware of. I just updated the URP import script to automatically load the kinematics from this new format of URP files.

You can place this script here:
C:/RoboDK/Library/Scripts/

And re-run the procedure.
This script will be provided by default with new versions.

By the way, the URP file you provided is from a UR5 robot, not a UR3.

Albert


Attached Files
.py   UR_LoadControllerKinematics.py (Size: 5.46 KB / Downloads: 65)
  




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