More than one base link?

[DaniCoimbra]

Hello, in my robot configuration I need two links to be connected to world and fixed, how can I setup that robot?
A fixed joint with the two links creates a closed articulation, and 2 joints connected to "World" also creates a closed articulation...

Is there a known way to implement this?

edit: in other words, is curobo limited to open articulations? are closed articulations supported?

[balakumar-s]

Closed kinematic chains are not supported. However, some closed chains can be formulated as open chains with mimic joints. One example is the robotiq 2f-140 gripper. Here is how it's represented with mimic joints:

curobo/src/curobo/content/assets/robot/ur_description/ur5e_robotiq_2f_140.urdf

Line 624 in 0c51dd2

<mimic joint="finger_joint" multiplier="-1" offset="0" />

If your closed chain can be represented as an open chain with mimic joints, then you could use cuRobo.

From your question, it looks like you have two fixed joints connecting 1 link (hip-link?) to the ground plane through 2 links (legs?). Does it make sense to use hip-link as the base_link and convert everything to be w.r.t. hip-link? Then there is no closed kinematic chain.