Pancake stepper motor is a special motor that controls the motor step by electric pulse. Its structure is similar to that of DC motor, mainly composed of stator, rotor, end cover, rotor shaft, front and rear plates and stator coil. Pancake stepper motor can convert electric pulse signal into corresponding angular displacement or linear displacement. For each input pulse signal, the rotor rotates an angle or moves forward. The output angular displacement or linear displacement is proportional to the input pulse number, and the speed is proportional to the pulse frequency.