报错如下：
[joint_state_publisher-1] process has died [pid 3800, exit code 1, cmd /opt/ros/kinetic/lib/joint_state_publisher/joint_state_publisher__name:=joint_state_publisher __log:=/home/dhy/.ros/log/aedcdbd8-6408-11e8-abc6-000c292730e7/joint_state_publisher-1.log].
[joint_state_publisher-1] process has died [pid 3800, exit code 1, cmd /opt/ros/kinetic/lib/joint_state_publisher/joint_state_publisher__name:=joint_state_publisher __log:=/home/dhy/.ros/log/aedcdbd8-6408-11e8-abc6-000c292730e7/joint_state_publisher-1.log].最后原因是这个
即以</robot>结尾 ，后面不能有换行，我这里多了一行，解决方法，去掉这一行即可。保存
终端输入：这里视自己文件具体操作
roslaunch ros_robotics ddrobot_rviz.launch model:=dd_robot2.urdf运行后添加RobotModel 和TF，结果如下
