<robotics> The use of motion sensors to determine a robot's
change in position relative to some known position. For
example, if a robot is traveling in a straight line and if it
knows the diameter of its wheels, then by counting the number
of wheel revolutions it can determine how far it has traveled.
Robots will often have shaft encoders attached to their drive
wheels which emit a fixed number of pulses per revolution. By
counting these pulses, the processor can estimate the distance
traveled.
