programming robots is on different levels .

for example if the robot has wheels , you need to program to turn on the actuators , which drive the wheels. done usually by PWM .

and then there are programs which are brains of the robot , which instill behaviors in robots .( ex: robocup ).

there are programs for several types of tasks of the robot.

you might try some introductory book on robot architecture or read a general paper on robot architectures .