Launch robot using sdf file

Hi, I have a urdf robot model. To make the ros gazebo bumper plugin work, I had to convert the urdf file to the sdf format and make some custom changes. Now I need to load updated sdf robot model instead of the urdf model. Launch file: The launch file doens't work. When I load the robot model by hand, the visualization is buggy and I get the following warning. rosrun gazebo_ros spawn_model -file /home/*****/summit_xl_omni.sdf -sdf -model test -y 0.0 -x -0.0 [WARN] [1516896999.247439, 0.260000]: Controller Spawner couldn't find the expected controller_manager ROS interface. Does anybody know how to properly call a sdf file which was converted from a urdf file per hand?