Here is a diagram of the top plate:

The top plate can be placed in a hollow tube. If we want to put anything on top of the robot, we can put it on the top plate. On the middle plate, we can put vision sensors, PC, and so on for processing.

These are the main structural elements that we need for this robot. These drawing can be develop in any CAD software like AutoCAD and LibreCAD. AutoCAD is a proprietary software whereas LibreCAD is free (http://librecad.org/cms/home.html). We have used LibreCAD for developing the preceding sketches.

You can simply install LibreCAD in Ubuntu using the following command:

    $ sudo apt-get install librecad

In the next section, we can see how we can model the robot in 3D. The 3D modeling is mainly using for robot simulation.