initial readme (#6)

README.md

@@ -1,3 +1,29 @@
 # tesseract_ros_workcell
 
-![](workcell1.png)
+This repo contain two main applications application_positioner and application_rail
+
+## Application positioner
+It can be launched using the following command `roslaunch twc_application application_positioner.launch`
+
+**Note**: set the argument application to true as follows:
+`  <arg name="application" default="true" />`
+
+The application as shown is a robot arm act as a raster for the point in the surface
+
+![application_positioner](workcell1.png)
+
+### Overview
+
+The robot preform two types of motion:
+
+* Free space motion: `tesseract_planning::PlanInstructionType::FREESPACE`
+* Linear motion: `tesseract_planning::PlanInstructionType::LINEAR`
+
+At the beginning, the robot preform free space motion from the start position to the first point in the path.
+
+then it perform Linear motion  when moving in
+a raster segment(a group points next to each other represent one swap or scan of raster).
+
+then from the end of one raster segment to the beginning of another raster segment.
+
+At the end of the program it preform a frees pace motion to the starting point(Home position).