[Melodic][Noetic] [WARN]: Controller Spawner couldn't find the expected controller_manager ROS Interface

[seanyen]

When you run your robot inside the simulator (for example, Gazebo), and you will see this messages and found your robot controller is not running completely.

[WARN]: Controller Spawner couldn't find the expected controller_manager ROS Interface

This could be to do with many reasons. But this issue is to share a common one seen when working with the simulator.

One possible cause is that the interface was advertised too late than the Controller Spawner was expecting (by default, it waits for 30 seconds). And if this occurred to you, you may set the timeout to wait indefinitely to accommodate the performance issue.

For example, in your ROS workspace, look for the launch file running the spawner and add the --timeout 0 as part of the args. This edit will ask Controller Spawner to wait forever.

  <node name="controller_spawner" pkg="controller_manager" type="spawner"
        args="--timeout 0 xxx_joint_publisher xxx_velocity_controller" />