Distributed components
======================

Distributed Model
-----------------

SEGA divides its components into a few layers. Namely, a layer that manages all
the communication with the Simulation, a low-level layer that manages and 
processes sensor data and a high level layer which mainly focusses on using the 
processed sensor data to create complex structures that can be used for
controlling the robot. (Think of calculation distances to specific objects and
approximating our current position on our map)
The final layer is the actual AI component, that glues the uses the high level
layer to make decisions on controlling the robot movement and actions that it
will take.

All components in these layers are nodes in a distributed system; each node can
run on a different machine.

Components
----------

The components in SEGA are:

    *   The simulation component is more or less a granted component, and is 
        provided by USARSim. 
        It is used to control the robot. We read and write data to the
        simulation. Sensor data is acquired through reading, moving the robot 
        is aquired through writing data over the network.

    *   The :ref:`net-net` relays messages from the simulation to other 
        components.

    *   Low level components; this layer contains sensors plus the steering
        component.
      
        -   The :ref:`wheels` component is used to control the robot. It uses the
            USAR Protocol to control movement of the robot.

        -   The robot has 8 :ref:`sonar` sensors, all of which returns a distance to 
            the object that reflect the sound. 
            
            Each of these distances are turned into 2d points by our
            sonar processor.

        -   The robot has a :ref:`laser` sensor. The laser sensor returns 180 
            distances, each associated with a different angle. 
            
            These distances are also turned into 2d points.
            (Just like the :ref:`sonar`)

        -   The :ref:`odometer` returns the x and y coordinates the robot has ridden, 
            plus the angle of the robot.
            
            This information is incredibly useful when creating the map,
            as it is essential to know what angle you are facing.


    *   High level components; 
    
        -   Path Planner

        -   Position

        -   Map