Why can't I control the second robot in the simulation?

I'm having problem launching and controlling two robots in one Gazebo simulation. I have set a namespace for each of them, but at certain parts of the code I'm not sure if it's the right way. I list all the relevant parts of files regarding launching the simulation below. When I launch the simulation, the simulation starts with both robots and the robot1 can be controlled as expected. As for robot2, even though there is the command topic for the joint in the topic list, when I publish a velocity to it through command line, it doesn't move. At the last terminal output at the bottom of the question you can also see, that the `robot_state_publisher` is not running for the robot2. There is an error in the launch terminal output regarding that, also shown below. Namely: [robot2/robot_state_publisher-8] process has died [pid 20402, exit code 255, cmd /opt/ros/kinetic/lib/robot_state_publisher/robot_state_publisher /joint_states:=/robot2/joint_states /robot_description:=/robot2/robot2_description /tf_prefix:=/robot2/tf_prefix __name:=robot_state_publisher __log:=/home/linux/.ros/log/8c080f7c-2895-11e9-b08b-b8ca3aa30f44/robot2-robot_state_publisher-8.log]. log file: /home/linux/.ros/log/8c080f7c-2895-11e9-b08b-b8ca3aa30f44/robot2-robot_state_publisher-8*.log My question is what am I doing wrong, because it seems I have tried everything and nothing works. launch for the robot2: control.launch: control yaml for the robot2: robot2_joint_state_controller: type: joint_state_controller/JointStateController publish_rate: 50 arm_base_joint1_controller: type: effort_controllers/JointVelocityController joint: arm_base_joint1 pid: {p: 1.0, i: 0.1, d: 0.01} description of the controlled joint of the robot2 in URDF: transmission_interface/SimpleTransmissionhardware_interface/EffortJointInterfacehardware_interface/EffortJointInterface1/robot2gazebo_ros_control/DefaultRobotHWSimtruerobot2_description terminal output after launching the simulation: started roslaunch server http://linux-Precision-T1650:41443/ SUMMARY ======== PARAMETERS * /robot1/joint_rear_left_wheel_controller/joint: joint_rear_left_w... * /robot1/joint_rear_left_wheel_controller/pid/d: 0.0005 * /robot1/joint_rear_left_wheel_controller/pid/i: 0.5 * /robot1/joint_rear_left_wheel_controller/pid/p: 2.0 * /robot1/joint_rear_left_wheel_controller/type: effort_controller... * /robot1/joint_rear_right_wheel_controller/joint: joint_rear_right_... * /robot1/joint_rear_right_wheel_controller/pid/d: 0.0005 * /robot1/joint_rear_right_wheel_controller/pid/i: 0.5 * /robot1/joint_rear_right_wheel_controller/pid/p: 2.0 * /robot1/joint_rear_right_wheel_controller/type: effort_controller... * /robot1/joint_state_controller/publish_rate: 50 * /robot1/joint_state_controller/type: joint_state_contr... * /robot1/robot_description: