URDF Importer base_link not connected to first link (panda robot)

Questions & Answers
1

I imported the panda.urdf with the URDF-Importer plugin into unity.

I disabled gravity on the robot Gameobject since otherwise it would just fall down.

I specified the target of the revolute joint in link4 to be approx. 40 degrees and when I enter the play mode the robot starts moving. However, the base_link was not connected to link1 and made a weird motion.

See my screenshot: Imgur: The magic of the Internet

Why are these links not connected?

I’m running my physics simulation in Gazebo and just need to visualize the robot model in Unity. Thus I don’t need a real “controller”. I just want to set the joints to a specific angle when a ROS message is received. Is it the correct way to set the target in the xDrive?

Any help is highly appreciated
Best, Marc

2

I found that it is related to this problem:
https://forum.unity.com/threads/root-articulation-body-choice.1234654/

The solution was to add a base_footprint link that is connected to the base_link.

Setting the joint positions programatically can be achieved by following this post:
https://forum.unity.com/threads/reset-pos-rot-of-articulation-bodies-manually-without-a-cacophony-of-derp.958741/