if you're looking to use an axis as your motor control:
1. joystick(whichever joystick you're using).GetRawAxis(#), i can't remember the axis numbers but if you do a print statement, for all the different axis.
2. look into using a encoder or potentiometer (feedback) thus you can use a pid loop. for more info about pid loops, check:
http://www.simbotics.org/resources/controls
3. joystick tips, use a limit function to limit the output of the joystick. also a dead band function helps with the problem that most joysticks don't go back to zero often or at all