A servo system mainly consists of a servo controller, drive circuit, servo motors and corresponding feedback detectors.
1. Principles of Servo Systems
When a manual control signal is received by the servo control system, the actuator performs a series of movements and actions according to the control signal instructions. If no more signals are present, the controlled transmitting device ceases operation until the control signal arrives.
2. Classification of Servo Systems
(1) According to your different target objects
Based on the different objects of their action, they can be divided into position servo systems and speed servo systems.
1) Position Servo System
This refers to a servo system that can accurately track and position the target command position. Depending on the presence of feedback, position servo systems are divided into open-loop control and closed-loop control.
The open-loop position servo system has the advantages of simple structure and low cost, but it does not have position and speed feedback functions. Its position control accuracy depends on the step angle of the stepper motor and the accuracy of the transmission mechanism.
Closed-loop control is divided into full closed-loop control and semi-closed-loop control. Under full closed-loop control, the detector directly detects the displacement of the controlled object on the bench and returns this displacement to the controller to form full closed-loop control.
Because the controller can control according to the actual displacement of the controlled object, full closed-loop control has a high positioning accuracy and can eliminate errors throughout the process, from the motor to the mechanical transmission mechanism to the controlled object.
However, the closed-loop control structure is relatively complex, the cost is high, and it is difficult to implement.
(2) Speed Servo System
The load torque of normally driven machines fluctuates frequently, as do the voltage and frequency of the power supply. Consequently, the operating speed of the driven object is generally variable.
Therefore, the main task of the speed servo system is to maintain stable operation of the driven machine (or load) at the precise speed required (not just a single speed).
(2) According to your different execution engines
According to the different types of actuation motors, the system can be divided into Direct Current (DC) Servo Systems and Alternating Current (AC) Servo Systems.
1) DC servo system
A DC servo system refers to a servo system where the servo motor uses a direct current motor.
2) AC servo system
An AC servo system mainly consists of an AC servo driver (or controller) and an AC servo motor. With the driver as its core, the system controls the operation of the AC servo motor.
Closed-loop control of torque, speed or position results in exceptional dynamic and static system performance.
Industrial robots comprise four main components: body, servos, reducers and controllers. Among these, the general structure of the electrical servo system of the industrial robot consists of three closed-loop controls: the current loop, the speed loop and the position loop.
Typically, for an AC servo driver, various functions such as position control, speed control and torque control can be achieved by manually setting its internal functional parameters.
A servomechanism, also known as a servo system, is a feedback control system designed to accurately follow or replicate a specific process. This servo system allows controlled outputs, such as the position, orientation, and status of an object, to automatically adapt to any changes in the input target (or set value).
The servo system is a product developed based on variable frequency technology. It is an automatic control system where the mechanical position or angle is the object of control. In addition to controlling speed and torque, the servo system can also realize precise, fast and stable position control.
In a broader sense, a servo system is a control system that accurately tracks or replicates a certain process and can also be called a tracking system.
In a more restricted sense, the servo system, also known as a position tracking system, controls the linear or angular displacement of a mechanical load in space. When the positional set value (input) changes arbitrarily, the main task of the system is to quickly and accurately replicate changes to the set value.
