How to build a tracked robot ?

If there is a design that combines speed ,power ,maneuverability,control thats track drive.You must have seen this design in a battle tank ,bull dozer and lots of off road vehicles .
Click on this picture to enlarge


Basically this kind of drive can be imagined as a vehicle that lays a track for itself as it moves.
And don't get tensed we are not going to build anything this complicated.
PRESSURE STUFF
So what this basically does is spreads out the weight evenly,as a result more traxion.Consider this example For instance, the ground pressure of a car which may weigh a tonne is equal to the pressure of the air in the tires, perhaps 30 psi (207 kPa), whereas the seventy-tonne M1 Abrams tank has a ground pressure of just over 15 psi (103 kPa).(amazing isn't it ).So as the ground pressure is less the vehicle rarely gets stuck when it goes off road .Well how are we going to build a robot like this ......Lets see.
LETS BUILD
First consider the size of your robot and choose a rubber belt according to the size of your robot.The belts come in varying shapes and sizes.Small like this one


If you want to make a bigger bot you can go for industrial belts with custom made sprockets and boogie wheels .I know a place in Chennai where you get those belts .I'll put the address in a few days.This is the industrial belt available.

MACHINING SPROCKETS AND BOGIE WHEELS
Sprockets can be machined from poly carbonate rods available commercially .And the machining process is normal like machining a metal and the same tools can be used .
BUILDING THE CHASSIS
The chassis can be built by conventional methods by using a plywood ,sheet metal or u can build your own chassis by welding metal pipes or flat rods.
STEERING
The tank uses a differential steering mechanism.
These are the pictures of bots which have used the same materials that I mentioned .Take a look at it.


The first one had used a plywood base and second one a sheet metal..
So start building good luck:) !!!!!!!