Add dual-arm LBR demo support to rolling

[kenichi-maeda]

This adds the dual-arm demo support from #386 to rolling.

Includes:

• lbr_dual_arm_bringup
• lbr_dual_arm_description
• lbr_dual_arm_moveit_config
• dual-arm mock and hardware bringup launches
• dual-arm MoveIt/RViz configuration

The package layout and version sync follow the cleanup from #392, with stale Humble wording removed.

Thanks @mhubii for preparing the Rolling cleanup in #392. Could you double-check that this branch matches the
intended rolling layout/versioning?

[mhubii]

thank you very much for creating this PR against rolling, let's get this merged by end of the week

[mhubii]

Okay, so I:

• merged bringup and description package (for self-containment in this demo)
• updated launch files (declarative, refer ROSCon livestream at 6 hours, 10 minutes)
• removed namespace from MoveIt for this demo (quite a pain to set this up correctly)
• added launch arguments for robot poses ros2 launch lbr_dual_arm mock.launch.py lbr_one_x:=0.0

Some questions:

1. Does this package layout make sense to you?
2. Do you need the namespace here?
3. When running MoveIt, dual-arm collisions are not avoided. This needs fixing before merging.

Thanks for any input you can provide!

Some related dual setup: https://moveit.picknik.ai/main/doc/examples/dual_arms/dual_arms_tutorial.html

[kenichi-maeda]

1. Yes, the new package layout makes sense to me.
2. No, I don't need the namespace. Since the two arms already use prefixed joint and link names, the robot model should remain unambiguous.
3. I can't think of a good solution for that at the moment, but I can look into it later.

Thank you for your work!

[mhubii]

Had another look. The issue might be dynamically adjusting the robot pose.

Somehow MoveIt avoids collisions for the default pose (y=0.5, y=-0.5), but not for others.

Likely because the move group just loads the robot description manually during launch:

https://github.com/kenichi-maeda/lbr_fri_ros2_stack/blob/6bde65a437faf6092d50ca675bcd510d069e32dc/lbr_demos/lbr_dual_arm/lbr_dual_arm_moveit_config/launch/move_group.launch.py#L20

The move group does not seem to be loading it dynamically from the robot state publisher.

In that case, either:

1. remove dynamic adjustment, and keep your initial suggestion:
   https://github.com/kenichi-maeda/lbr_fri_ros2_stack/blob/653b74e1ee3d687121a21a9c02e730e5cd9c2b6d/lbr_demos/lbr_dual_arm/lbr_dual_arm_description/doc/lbr_dual_arm_description.rst

Or

2. add a configurable pose to the move group launch file (may lead to user error)

Or

3. see whether this can be fixed for MoveIt. Related issue: Load robot_description from topic moveit/moveit2#2291

Sorry I should have double checked this. On humble (with fixed pose) this is not an issue.

[mhubii]

fix dynamic robot pose for MoveIt

[mhubii]

went with option 2: configurable move group. move_group.launch.py now included into hardware.launch.py / mock.launch.py to guarantee single source for pose

[mhubii]

/backport

[github-actions]

Backport branch created but failed to create PR.
Request to create PR rejected with status 403.

(see action log for full response)

[kenichi-maeda]

Thanks @mhubii for fixing the dynamic pose / MoveIt setup! I'm pretty sure a lot of people will find this useful for setting up dual arms :)

[mhubii]

thanks, appreciate that. Thanks also for your heavy lifting.

what remains now is:

• fixing hardware related sensor naming: Support multi-arm setups on single node #387
• investigating some collision margin (the tolerance seems quite low right now)