Denavit Hartenberg (DH) extractor gives incomplete parameters

[pab]

I selected a UR5 model from the model library. Dragged drop it on the scene. Then I went to the last link "connection". Then I clicked Modules > Kinematics > Denavit Hartenberg parameters. I get the following

Denavit-Hartenberg parameters:
- between joint '/Joint{0}' and joint '/Joint{1}': d=0.0880 [m], theta=90.0 [deg], r=0.0003 [m], alpha=90.0 [deg]
- between joint '/Joint{1}' and joint '/Joint{2}': d=0.0000 [m], theta=-0.0 [deg], r=0.2101 [m], alpha=0.0 [deg]
- between joint '/Joint{2}' and joint '/Joint{3}': d=0.0006 [m], theta=0.0 [deg], r=0.0300 [m], alpha=90.0 [deg]
- between joint '/Joint{3}' and joint '/Joint{4}': d=0.1265 [m], theta=90.0 [deg], r=0.0005 [m], alpha=90.0 [deg]
- between joint '/Joint{4}' and joint '/Joint{5}': d=0.0006 [m], theta=-0.0 [deg], r=0.0005 [m], alpha=90.0 [deg]

Note there are 5 DH parameters. But the UR5 has 6 joints and should have 6 DH parameters. I get the same result with other manipulators.

I have tried this on 4.5 as well as 4.6 with the same result.

Also, please list the convention used for DH parameters. For example, the book Introduction to Robotics: Mechanics and Control by John Craig and Robot dynamics and control by Spong et al use different parameterizations for Denavit Hartenberg.

[coppelia]

Hello,

we are using the classic DH convention. And ignoring all non-joint objects, since the end-effector could have any relative frame depending on the object type. But we have now modified the Denavit-Hartenberg extractor add-on to also take anyways the end-effector object into consideration.

Cheers