Servo system, precise feedback control system

Servo system is essentially a follow-up system, only the controlled quantity is displacement or its derivative to time.If you ask what a follower system is, it is the output of a system that reproduces the input signal as fast and precisely as possible， It is measured by overshoots and delays.

Servo system is an automatic control system which enables the output of object such as position, direction and state to change arbitrarily with the input target (or given value).The main task of the servo system is to amplify, transform and control the power according to the control command, so as to make the output torque, speed and position control of the drive device very flexible and convenient.

Principle of Servo System

The control object of servo system is the displacement and speed of coordinate axis of machine tool, and the actuating mechanism is servo motor or stepping motor. The part that controls and amplifies input command signal is called servo amplifier (also called servo driver, servo unit, etc.), which is the core of servo drive.

The servo system is mainly composed of three parts: controller, power drive device, feedback device and electric motor.The controller adjusts the control quantity according to the difference between the given value of the CNC system and the actual operation value detected by the feedback device.

As the main circuit of the system, power drive device acts the electric energy in the power grid on the motor according to the control quantity and regulates the torque of the motor. On the other hand, it converts the constant voltage and frequency power supply from the power grid into AC or DC power required by the motor according to the requirements of the motor; while the motor drives the motor according to the size of power supply.

Types of Servo Systems

1. From the nature of system components, there are electrical servo system, hydraulic servo system, electrical-hydraulic servo system and electrical-electrical servo system

2. From the physical properties of system output, there are speed or acceleration servo system and position servo system.

3. There are analog servo system and digital servo system according to the component characteristics and signal action characteristics included in the system.

4. From the structural characteristics of the system, there are single-loop servo system, multiple-loop servo system, open-loop servo system and closed-loop servo system.

5. Servo system is divided into stepping servo system, DC motor servo system and AC motor servo system according to its driving elements.