joint_trajectory_controller is used for executing joint space trajectories on a list of given joints. The trajectories to the controller are sent using the action interface, control_msgs::FollowJointTrajectoryAction, in the follow_joint_trajectory namespace of the controller.
More information about this controller is available at the following website: http://wiki.ros.org/joint_trajectory_controller.
Now, let's learn how to model the robot arm.
