just sharing our integration of the KUKA LBR robots here in the hope someone might find it helpful.
The ROS2 control
hardware_interface::SystemInterface is implemented via the Fast Robot Interface (FRI), which we integrated into the ROS2 build system. Everything is setup for MoveIt2 and for the Gazebo simulation. Supported are iiwa7, iiwa14, med7, med14. This is built for foxy, but it is a work in progress and other branches are to follow.