Locomotion

The locomotion system of a fighting robot describes how it moves around.

Differential Drive
In the differential drive locomotion scheme the robot moves using two wheels placed at either side of its chassis. Forward and backward motion is obtained by rotating each wheel in the same direction, while rotating the wheels in different directions results in turning motion.

In order to make the robot stable a third point of contact is needed, often using spherical bearing or caster wheel is used.

Skid - Steer Drive
Skid-Steer drive is a variation on differential drive where multiple wheels or tracks are used instead. This has the advantage of being able to cope with more uneven terrain. However this locomotion scheme does mean that some of the wheels/track will drag along the ground when turning.

Actuators
These devices convert electrical energy into mechanical energy.
 * Brushed DC Motor
 * Brushless DC Motor
 * Servo

Wheels
Wheels are a popular way to make robots move across relatively flat terrain efficiently and simply.

The wheel and the ground form a rack and pinion mechanism with the gear ratio being decided by the radius of the wheel. A larger wheel will mean that for the same angular movement the robot will move move further forward than a smaller wheel. However the larger wheel will also be harder to turn (require more torque).

Most wheels are formed of a hard inner centre and a softer tyre around the edge. Soft rubber tyres provide good traction and grip. However, the grip of cheaper hard tyres can be improved using rubber bands.

Maximising traction is important for giving your robot pushing power.

Tracks
Tracks have the advantage of distributing the weight of the robot over a larger area and will maintain grip over uneven terrain. However they will make your robot less maneuverable and add extra complexity to your design.