new behavior for placo and collisions

[askuric]

Repaired collision check with placo.

• Added simpified collisions in URDF
• Using placo's collision avoidance rather than the collision check from before

TAKEAWAY
Placo can now plan for the collisions and adapt the motor control to still be able to execute the task, rather than just collide with the robot body and hope the target is reached approximately.

WITHOUT collision avoidance	WITH collision avoidance
Robot body_yaw does not move - the head collides Kazam_screencast_00043.mp4	Robot body_yaw adapts to allow for low z position Kazam_screencast_00046.mp4
The robot's body_yaw movement planned without collisions so the head cannot look back when low Kazam_screencast_00042.mp4	The robot automatically set the body_yaw to be able to look back even if very low Kazam_screencast_00040.mp4

[RemiFabre]

I was able to reproduce the avoidance mechanism on an IRL Beta Reachy mini, the same type of movements shown in the simulation videos above. This is very cool!

However, even when multiplying x10 the values below, some collisions persisted:

This seems to be related to the cases where the collision model doesn't quite fit the physical model. Antun tried more complex shapes but it created instabilities.

This version is a clear improvement still, as in most cases the collision is greatly reduced. It should merged imo, good work!

For future readers that want to activate this, run the daemon as follows:
reachy-mini-daemon --kinematics-engine Placo --check-collision