Please follow the directions here https://github.com/ros-controls/ros2_control_demos to set up ros2_control, ros2_controllers, and ros2_control_demos.
For now the directory structure should look something like this to have everything compile:
colcon_ws/src
|
├── kuka_experimental (https://github.com/dignakov/kuka_experimental)
└── ros2_control_kuka_driver
The minimal ros2 fork of kuka_experimental has a, somewhat rough, adaptation of the RSI simulator. It can be used to test the driver by callig:
ros2 run kuka_rsi_simulator kuka_rsi_simulator
In combination with launching the robot hardware (see https://github.com/ros-controls/ros2_control_demos for details on starting the driver).