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When the controller manager loads a controller, it is in the stopped state. You need to explicitly start it to transition to a running state. You can check a controller's state by calling /controller_manager/list_controllers

This the usual flow:

Load a controller: Use the /controller_manager/load_controller service

• Precondition: Controller config loaded in the ROS param server.
• Effect: Calls the controller's init(...) method.
• Postcondition: Controller is loaded, but stopped.

Start a controller: Use the /controller_manager/switch_controller service (start_controllers field)

• Precondition: Controller already loaded and stopped. Resources to claim are available.
• Effect: Calls the controller's starting(...) method
• Postcondition: Running controller.

Stop a controller: Use the /controller_manager/switch_controller service (stop_controllers field)

• Precondition: Controller is running.
• Effect: Calls the controller's stopping(...) method
• Postcondition: Stopped (but still loaded) controller.

Unload a controller: Use the /controller_manager/load_controller service

• Precondition: Controller is stopped.
• Effect: Calls controller destructor.
• Postcondition: Controller no longer managed by the controller_manager.