Qualisys setup using duplicated marker arrangements

[magixn]

I am setting up crazyswarm2 with Qualisys using duplicated marker arrangements. I followed the doc of crazyswarm but met several problems. I listed all the things necessary and it might be helpful for others.

1. duplicated marker arrangements mean marker arrangements can be similar, since markers are pasted by hand, not very accurate.
2. Old hover_swarm.launch is not necessary. Is it right?
3. In motion_capture.yaml, sample is mocap_deck

• set type and hostname
• mode should be libRigidBodyTracker?
• points is absolute position or relative position to the center of the fly? Now I think it is relative position so that the same marker arrangements can use one type of frame.
• I try to use libmotioncapture to get points. But python.py only returns rigidbody, and setting rigidbody for each marker by hand seems to be tedious. Any other solution?
• What about the setting of offset?

4. In crazyflies.yaml, sample is cf21_mocap_deck

• robot_types: motion_capture enabled, marker type.
• robots: initial position, type.

[whoenig]

• hover_swarm is not used anymore
• mode is actually also not used in the code
• points are relative (and can be shifted by using the offset)
• One would need to print the /pointCloud topic to get the points. Unfortunately this is not very user-friendly on the command line right now.

[magixn]

So I need to calculate the points by myself. When marker's absolute position minus position, which can derive from cfclient or somewhere else? I think it is the origin of base_link not base_footprint.

[whoenig]

No "calculation" needed. One just puts the Crazyflie with markers attached and then prints out the resulting point (either with a custom ROS2 node or by using the vendor SDK examples directly).

[magixn]

I am a little confused. If I have duplicate/the same marker arrangement for several Crazyflies, what should I do? Doe it means that using the same marker_configurations does not need points with so accurate relative position? The answer means that just set the points measured from that in origin for all.

[whoenig]

It's relative to the body frame. So I usually put the drone at the origin to collect the points.