Hi all, I'm working on a project currently, a robot has closed loop kinematic for this reason I've converted urdf to sdf file. It worked closed loop kinematic. Actually I want to control robot's joint each of them. I am using gazebo9 and ros melodic version. I've searching how to control joint for sdf file robot for days. People usually use urdf/xacro file robot and default effort,velocity,position controller work with it. I found some plugin to control position joint but when I compile catkin build or catkin make, it was error. What can I do overcome this problem? Some references: - Using SDF instead of URDF with ROS Robot State Publisher:https://answers.gazebosim.org//question/25511/using-sdf-instead-of-urdf-with-ros-robot-state-publisher/ - Sending joint commands with ROS - https://classic.gazebosim.org/tutorials?tut=drcsim_ros_cmds&cat=drcsim - Setting Velocity on Links And Joints - https://classic.gazebosim.org/tutorials?tut=set_velocity&cat=