Update README.md

README.md

+# Description
+
+The iri\_dynamixel\_pan\_tilt\_msgs ROS package contains specific messages definitions for the [iri\_dynamixel\_pan\_tilt\_driver](https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_driver).
+
+### ROS services provided
+
+- [getPose](https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_msgs/blob/master/srv/getPosition.srv):
+ To get the current pose of both servos.
+
+- [setMode](https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_msgs/blob/master/srv/setMode.srv):
+ To set the servos controller's mode.
+
+### ROS actions provided
+
+- [scan](https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_msgs/blob/master/action/scan.action):
+ To perform an horizontal scan with a tilt angle.
+
+# Dependencies
+
+This node has the following dependencies:
+
+ * [message_generation](http://wiki.ros.org/message_generation)
+ * [std_msgs](http://wiki.ros.org/std_msgs)
+ * [sensor_msgs](http://wiki.ros.org/sensor_msgs)
+ * [actionlib_msgs](http://wiki.ros.org/actionlib_msgs)
+
+# Install
+
+- Move to workspace: `roscd && cd ../src`
+- Clone the repository: `git clone https://gitlab.iri.upc.edu/labrobotica/ros/devices/dynamixel_pan_tilt/iri_dynamixel_pan_tilt_msgs.git`
+- Compile:  `roscd && cd .. && catkin_make -DCMAKE_BUILD_TYPE=Release`
+
+However, this package is normally used as part of a wider installation (i.e. a 
+robot, an experiment or a demosntration) which will normally include a complete 
+rosinstall file to be used with the [wstool](http://wiki.ros.org/wstool) tool.
+
+