Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
DH Parameters – Standard / Modified
#1
Hello!

RoboDK provides easy access to the DH parameters of the robot (in our case UR5). Basically, the RoboDK environment provides access to the modified DH parameters. We would need information about the real standard DH parameters. It is possible to obtain information about the real standard DH parameters?

Thank you and best regards!

MG
#2
Hello!

I found how we can get DH parameters (nominal-real / DH-MDH). However, I noticed that the parameters in the different command windows do not match. Maybe does anyone know why such a difference (see picture below - in the attachment)?


Thank you and best regards!

MG


Attached Files Thumbnail(s)
   
#3
Hello!

Does anyone know why this difference occurs?

I would also expect that the real (from the robotic controller) values of the DH-parameters would be slightly different, depending on the nominal model. In this case, the real values of the DH-parameters almost match with the values of the nominal model!
 
Does 'Accurate' refer to real (robotic controller) DH-parameter values?

Best Regards.

MG
#4
I'm not sure why you see a difference.

Did you see any warning messages when exporting the DH table?
Can you provide the robot as a robot file or the RDK file?
#5
Hello!


If you compare the left and right tables, the values are not exactly the same.


We also assume that 'Accurate' refer to real (robotic controller) DH-parameter values - is this correct?


In the attachment I attached a .urp file with which we get real (Accurate) DH parameters.


Best Regards.

MG


Attached Files
.urp   kinematics_pars_ur5_cb.urp (Size: 1.22 KB / Downloads: 29)
#6
Hello!

Can anyone explain why the values in both tables are not the same?

Thank you and best regards!

MG
#7
Hi Mitja,

I see, you updated your robot kinematic with RoboDK.
These values won't match.
We've used tools that we already had for calibration in order to do the UR kinematic update, but that makes theses values unusable.
These values only make sense if the calibration is done using a laser tracker or an optical CMM.

Jeremy
#8
Hello!

Thanks for the information.

If I understand correctly now, the MDH parameters are refreshed in the command window 'Robot Parameters'.
However, the values in the command window 'UR5-Export Robot Kinematics' are incorrect.

We would like to get updated values of DH (not MDH) parameters for our UR5 robot. Is there (in the RoboDK) then any possibility to get updated DH-parameters?

Thanks and best regards.

MG
#9
Hi Mitja,

Not directly from RoboDK.
You might try to do the maths on your own, but it's not an easy task to go from DHM to DH.

Jeremy
  




Users browsing this thread:
1 Guest(s)