Melodic updates

docs/source/1-ros-basics.rst

@@ -44,7 +44,7 @@ Official definition on ROS WiKi is:
 
 .. line-block::
 
-  ROS is an open-source, meta-operating system for your robot. It provides the services you would expect from an operating system, including hardware abstraction, low-level device control, implementation of commonly-used functionality, message-passing between processes, and package management. It also provides tools and libraries for obtaining, building, writing, and running code across multiple computers. ROS is similar in some respects to 'robot frameworks, such as Player, YARP, Orocos, CARMEN, Orca, MOOS, and Microsoft Robotics Studio.
+  ROS is an open-source, meta-operating system for your robot. It provides the services you would expect from an operating system, including hardware abstraction, low-level device control, implementation of commonly-used functionality, message-passing between processes, and package management. It also provides tools and libraries for obtaining, building, writing, and running code across multiple computers.
 
 System Setup
 ^^^^^^^^
@@ -61,9 +61,9 @@ Run the script to install, will take some time.
 
   bash ubuntu_sim_ros_melodic.sh
 
-You might need to re-run two previous commmands if you get some erros.
+You might need to re-run two previous commmands if you get some errors.
 
-Next step execute below commands to install and build PX4 Firmware
+Next step, execute below commands to install and build PX4 Firmware
 
 .. code-block:: bash