DC servo motor is divided into brush and brushless motors. Brush motor low cost, simple structure, large starting torque, speed range is wide, easy control, the need to maintain, but easy to maintain (for carbon brush), electromagnetic interference, the environment they require. Therefore, it can be used for cost-sensitive general industrial and civil occasions.
    Brushless motor small size, light weight, to contribute to large, fast response, high-speed, inertia is small, smooth rotation, torque and stability. Control of complex, easy to implement intelligent, their electronic commutation flexible and can be square wave commutation or sinusoidal commutation. Electrical maintenance-free, efficient, low operating temperature, electromagnetic radiation is very small, long-life, can be used for a variety of environments.
    AC servo motor is brushless motor, is divided into synchronous and asynchronous motor, the current motion control is generally used in synchronous motor, its power range, can do a great power. Large inertia, the maximum rotation speed is low, and the rapid decrease with the increase of power. And therefore suitable for low-speed smooth running of applications.
    Servo motor is a permanent magnet inside the rotor, the drive control of U / V / W three-phase electricity to form electromagnetic field, the rotor under the influence of this magnetic field rotation, while built-in encoder motor feedback signals to the drive, the drive values and goals based on feedback value comparison, adjusting the angle of the rotor rotation. Determined by the precision of servo motor encoder accuracy (line number).