[EricH]

Originally Posted by mahmosh

our team want to use a servo for driving the robot not to use the camera
... not like HITEC HS-475HB servos

In that case, Indysam's answer stands.

<R52>Items specifically PROHIBITED from use on the ROBOT include:
A. Electric motors and/or servos different from, or in addition to, those in the Kit Of Parts, with the exception of those specifically permitted by Rule <R51>.
B. Electric solenoid actuators (note: electric solenoid actuators are NOT the same as pneumatic solenoid valves – the latter are permitted, the former are not).

I don't see any step motors/servos in the list in <R51>...

Now if you could rig a CIM or other KOP motor to act like a step motor or servo through some clever software and sensors, without modifying the motor itself...