Roslaunch

roslaunch allows you to do the following

• Launch the ROS Master and multiple nodes with one simple command
• Set default parameters on the parameter server
• Automatically re-spawn processes that have died

To use roslaunch , you must first make sure that your workspace has been built and sourced:

$ cd /home/workspace/catkin_ws/
$ catkin_make

Once the workspace has been built, you can source it’s setup script:

$ source devel/setup.bash

With your workspace sourced you can now launch simple_arm :

$ roslaunch simple_arm robot_spawn.launch

And there you have it! Your very own two-degrees-of-freedom arm in simulation!