Add README.md

README.md

+# Description
+
+This ROS package contains the launch and xacro files to set up and configure and simulate a Dynamixel pan&tilt device in ROS.
+
+# Dependencies
+
+This node has the following ROS dependencies:
+
+  * [Joint Trajectory Controller package](http://wiki.ros.org/joint_trajectory_controller?distro=kinetic)
+  * [Joint State Controller package](http://wiki.ros.org/joint_state_controller?distro=kinetic)
+
+This dependencies can be installed with the following command:
+
+```
+sudo apt-get install ros-kinetic-joint-trajectory-controller ros-kinetic-joint-state-controller
+```
+
+This node has the following ROS IRI dependencies:
+
+  * [IRI Dynamixel pan&tilt description](https://gitlab.iri.upc.edu/labrobotica/ros/devices/ptu_d46/iri_dynamixel_pan_tilt_description).
+  
+# Installation
+
+- Move to workspace: `roscd && cd ../src`
+- Clone the repository: `git clone https://gitlab.iri.upc.edu/labrobotica/ros/devices/ptu_d46/iri_dynamixel_pan_tilt_gazebo.git`
+- Compile:  `roscd && cd .. && catkin_make -DCMAKE_BUILD_TYPE=Release`
+
+# How to use it
+
+This dynamixel pan&tilt model is automatically included when a dynamixel pan&tilt device is included in a xacro or urdf file. 
+
+There is an example launch file named [ax12_pan_tilt_sim.launch](https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_gazebo/blob/master/launch/ax12_pan_tilt_sim.launch).