How to use the factory DH-calibration of the UR-Arms?

asked 2017-05-21 05:34:59 -0500

NEngelhard gravatar image

updated 2017-05-21 05:35:56 -0500

Hey!

I'm using several UR-Robots with the ur_modern_driver and packages from ros-industrial. The provided urdfs work well, but only contain the default values of the DH-parameters. This means that there is an offset of several mm between the tool pose used e.g. in MoveIt and the pose that is sent by the UR-controller as UR does a factory calibration to get more accurate DH-parameters for every robot. I can read the dh-offsets from the controller but still can't reproduce the controller's values.

Did anyone succeed in using this values? Accurate poses for all joints are also important for extrinsic calibration if a camera is attached to a link other than the tool. This would also be a great improvement to the drivers (automatic adaption of the urdf for the connected robot)

Nikolas

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Comments

I see the benefit of having this on ROS Answers, but the ur_modern_driver issue tracker has an almost exact duplicate of your question. See ThomasTimm/ur_modern_driver#108.

gvdhoorn gravatar image gvdhoorn  ( 2017-05-21 06:01:37 -0500 )edit

See also ThomasTimm/ur_modern_driver#16 btw. Apparently even with the D-H parameters used the reported pose is still not exactly the one given by the TP / published on tool0_controller.

gvdhoorn gravatar image gvdhoorn  ( 2017-05-21 06:06:08 -0500 )edit

I hoped to find more people here as the discussion on bitbucket died down.

NEngelhard gravatar image NEngelhard  ( 2017-05-21 10:22:56 -0500 )edit