Unable to connect Gazebo to ROS_Control

I'm trying to follow the [Gazebo ROS Control tutorial](http://gazebosim.org/tutorials/?tut=ros_control) but when I run the line: roslaunch myrobot_gazebo myrobot_world.launch I get the error output: [ INFO] [1430582458.651473605]: Finished loading Gazebo ROS API Plugin. [ INFO] [1430582458.655485962]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting... spawn_model script started [INFO] [WallTime: 1430582458.938102] [0.000000] Loading model xml from ros parameter [INFO] [WallTime: 1430582458.941118] [0.000000] Waiting for service /gazebo/spawn_urdf_model [ INFO] [1430582459.741922815, 0.023000000]: waitForService: Service [/gazebo/set_physics_properties] is now available. [ INFO] [1430582459.819138448, 0.096000000]: Physics dynamic reconfigure ready. [INFO] [WallTime: 1430582459.855947] [0.132000] Calling service /gazebo/spawn_urdf_model [INFO] [WallTime: 1430582460.083841] [0.295000] Spawn status: SpawnModel: Successfully spawned model [ INFO] [1430582460.118077443, 0.295000000]: Loading gazebo_ros_control plugin [ INFO] [1430582460.118570188, 0.295000000]: Starting gazebo_ros_control plugin in namespace: /myrobot [ INFO] [1430582460.120080182, 0.295000000]: gazebo_ros_control plugin is waiting for model URDF in parameter [/robot_description] on the ROS param server. [ERROR] [1430582460.223045545, 0.295000000]: No valid hardware interface element found in joint 'torso_to_front_right_leg_joint'. [ERROR] [1430582460.223576289, 0.295000000]: Failed to load joints for transmission 'torso_to_front_right_leg_joint_trans'. [ INFO] [1430582460.363040693, 0.295000000]: Loaded gazebo_ros_control. [urdf_spawner-3] process has finished cleanly log file: /home/chris/.ros/log/6b610a90-f0e4-11e4-bb58-001c1091e5ab/urdf_spawner-3*.log [ERROR] [1430582476.852961975, 16.562000000]: Exception thrown while initializing controller torso_to_front_right_leg_joint_position_controller. Could not find resource 'torso_to_front_right_leg_joint' in 'hardware_interface::EffortJointInterface'. [ERROR] [1430582476.853310724, 16.563000000]: Initializing controller 'torso_to_front_right_leg_joint_position_controller' failed My robot's urdf is just a single box "torso" with a single box "leg", and all the joints and interfaces and transmissions are defined: falseGazebo/RedfalseGazebo/Bluefalsetransmission_interface/SimpleTransmissionEffortJointInterface1/myrobot myrobot_world.launch: However, Gazebo only renders the torso and not the leg, and complains about "torso_to_front_right_leg_joint" not existing, even though it's clearly defined in my URDF. Why is this? Edit: Based on [this question](http://answers.gazebosim.org/question/6654/gazeboos-x-109-no-valid-hardware-interface-element/), I found that this is actually a bug/typo in the tutorial, which tells you to specify transmissions like: transmission_interface/SimpleTransmissionEffortJointInterface1 which is incorrect, as they actually need to be defined like: transmission_interface/SimpleTransmissionEffortJointInterfaceEffortJointInterface1 That fixes the first error, but now I get a different error: This robot has a joint named "torso_to_front_right_leg_joint" which is not in the gazebo model. What does it mean by "not in the gazebo model"? Is this why the leg is still not showing up in Gazebo? I realize I don't have a tag for my joints, but the [Gazebo ROS tutorial](http://gazebosim.org/tutorials?tut=ros_urdf&cat=connect_ros) claims that these are optional for joints. Is this incorrect? Even if I add: I still get the same error.