example 2 does not have odom frame about ros2_control_demos

[patrickwasp]

I didn't read all the documentation, I should have started with https://github.com/ros-controls/ros2_control_demos/blob/master/doc/index.rst.

installing dependencies fixed the demo

rosdep update --rosdistro=$ROS_DISTRO
sudo apt-get update
sudo rosdep install --from-paths ./ -i -y --rosdistro ${ROS_DISTRO}

after that odom was published and the robot worked as expected, teleoperation with the following command.

ros2 run teleop_twist_keyboard teleop_twist_keyboard --ros-args --remap cmd_vel:=/diffbot_base_controller/cmd_vel_unstamped