The main function of the servo motor is to control the speed uniformly and stably with the change in voltage. The servo motor is mainly positioned by pulses. When receiving a pulse current, it will rotate the corresponding angle of a pulse accordingly, so that it is unique because the servo motor It also has the function of sending out a pulse current. Each time it rotates an angle, it will send a corresponding number of pulses, which corresponds to the pulses received by the servo motor, or is called a closed loop. In this way, the system will know how many pulses are sent to the servo motor. At the same time, how many pulses are received back, so that the rotation of the motor can be accurately controlled, and the precise positioning can reach 0.001mm.
DC servo motors are divided into brushed and brushless motors. Brushed motors have low cost, simple structure, large starting torque, wide speed range, easy control, and maintenance, but they are easy to maintain (replace carbon brushes), generate electromagnetic interference, and have environmental requirements. Therefore, it can be used in cost-sensitive general industrial and civil applications.
Brushless motor has small volume, light weight, large output, fast response, high speed, small inertia, smooth rotation and stable torque. The control is complicated and it is easy to realize intelligence. Its electronic commutation method is flexible and can be square wave commutation or sine wave commutation. The motor is maintenance-free, high efficiency, low operating temperature, small electromagnetic radiation, long life, and can be used in various environments.
The AC servo motor is also a brushless motor, which is divided into synchronous and asynchronous motors. At present, synchronous motors are generally used in motion control. It has a large power range and can achieve great power. Large inertia, low maximum rotation speed, and rapid decrease with increasing power. Therefore, it is suitable for low speed and stable applications.
The rotor inside the servo motor is a permanent magnet. The U / V / W three-phase electricity controlled by the driver forms an electromagnetic field. The rotor rotates under the action of this magnetic field. At the same time, the encoder's built-in feedback signal is sent to the driver. The driver according to the feedback value and target Compare the values and adjust the rotation angle of the rotor.