Servo motor working principle

    1. The servo mechanism is the position and orientation of the object.
An automatic control system that can control any change in the input target (or given value) such as the state. The servo is mainly positioned by pulse. Basically, it can be understood that when the servo motor receives one pulse, it will rotate the angle corresponding to one pulse to realize the displacement. Because the servo motor itself has the function of emitting pulses, the servo motor has every When you rotate an angle, a corresponding number of pulses are emitted, so that it responds to the pulse received by the servo motor, or closed loop. In this way, the system knows how many pulses are sent to the servo motor, and how many pulses are received at the same time. In this way, the rotation of the motor can be controlled very accurately, so that accurate positioning can be achieved, which can reach 0.001 mm. DC servo motors are divided into brushed and brushless motors. The brush motor has low cost, simple structure, large starting torque, wide speed regulation range, easy control, maintenance, but inconvenient maintenance (replacement of carbon brushes), electromagnetic interference, and environmental requirements. It can therefore be used in cost-sensitive general industrial and residential applications.
The brushless motor is small in size, light in weight, large in output, fast in response, high in speed, small in inertia, smooth in rotation and stable in torque. The control is complex, and it is easy to realize intelligence. The electronic commutation method is flexible, and can be square wave commutation or sine wave commutation. The motor is maintenance-free, has high efficiency, low operating temperature, low electromagnetic radiation and long life, and can be used in various environments.
    2. 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 a large power. High inertia, the highest rotational speed is low, and it decreases rapidly as power increases. Therefore, it is suitable for applications with low speed and smooth operation.
    3. The rotor inside the servo motor is a permanent magnet. The U/V/W three-phase electric motor controlled by the driver forms an electromagnetic field. The rotor rotates under the action of the magnetic field. At the same time, the encoder feedback signal from the motor is supplied to the driver. The driver is based on the feedback value. Compare with the target value to adjust the angle at which the rotor rotates. The accuracy of the servo motor is determined by the accuracy (number of lines) of the encoder.
The difference between the AC servo motor and the brushless DC servo motor: AC servo is better because it is sinusoidal control and the torque ripple is small. The DC servo is a trapezoidal wave. But DC servo is simpler and cheaper.