After getting done with the preceding topics, we can start commanding positions to each joint.

To move a robot joint in Gazebo, we have to publish a joint value with a message type std_msgs/Float64 to the joint position controller command topics.

Here is an example of moving the fourth joint to 1.0 radians:

    $ rostopic pub /seven_dof_arm/joint4_position_controller/command 
 std_msgs/Float64 1.0  

We can also view the joint states of the robot by using the following command:

    $ rostopic echo /seven_dof_arm/joint_states