Servo system selection introductory knowledge
Release time:
2020-06-12 11:52
Source:
Servo system (servomechanism), also known as servo system, is a feedback control system used to accurately follow or reproduce a process. The servo system enables the output of the object's position, orientation, state, etc. to follow the input target (or given value) of any change in the automatic control system. The servo system mainly consists of three parts: motion control card (device), servo drive and servo motor. This paper mainly introduces several important parameters in the process of servo drive selection and servo motor selection, and provides the introductory knowledge of servo system selection.
Servo drives (servo drives), also known as "servo controller" and "servo amplifier", are used to control a servo motor controller, which is part of the servo system and is mainly used in high-precision positioning systems. Generally, the servo motor is controlled by three ways of position, speed and torque to achieve high-precision transmission system positioning.
Servo drives are widely used in the field of injection molding machines, textile machinery, packaging machinery, CNC machine tools, etc. The typical application cases of AoTong servo drive system are used as reference: machine vision metal material analysis laboratory, electro-hydraulic servo hot press molding machine.
Machine Vision Metal Materials Analysis Laboratory
▲ Electro-hydraulic servo hot pressing molding machine
As we all know, the industrial operating environment is often more harsh, not only by the power supply voltage, working environment temperature, the impact of the operating environment; at the same time, according to the production needs, the precision control of the system, and feedback has a strong requirement, so there are many factors to consider, here mainly to introduce the choice according to the requirements of the system.
▲ Otong ATS20 naming rules: selection reference
From the naming rule parameter table, we can intuitively see the serial number, rated power, input voltage, control mode and encoder feedback type. One by one, I 'd like to give you an introduction:
Product serial number:
From the serial number, we can quickly locate the corresponding servo drive model.
Rated power and input voltage:
The voltage required by different power segments of the servo driver is different. The medium and small power segments such as 400w generally use single-phase AC220v, while the high-power servo such as 22Kw uses three-phase AC380v.
Control mode:
The servo drive has three control modes: torque, speed and position mode. These three control methods can be controlled by analog, pulse and bus. In practical application, simulation is mostly used for torque mode control, and less used in speed mode and position mode. Position mode can be controlled by pulse direction (P D), and pulse orthogonal coding (A B) may also be used in practical application. Bus control forms, such as Modbus/CANopen/EtherCAT, etc.
▲ATS20支持脉冲、Modbus/CANopen/EtherCAT
Encoder Feedback Type:
There are many kinds of feedback components and feedback sensors. According to whether to do closed loop, select feedback sensors, encoders, tachometer motors, resolvers, etc. If the system has a feedback element, at this time, when selecting the driver, it is necessary to consider whether the driver supports this feedback, the type of feedback, or the signal output form of feedback.
Second is the use of the environment:
The main consideration is the influence of temperature, as well as the working conditions and whether a protective cover is needed.
▲ Example of environmental factors: the ambient temperature of the casting plant is as high as 40 ℃
▲ ATS20 supports wide temperature working environment,-40 ℃ ~ 55 ℃
According to this information, we can roughly select the servo driver that matches the motor. In addition, as mentioned earlier, whether the installation size is appropriate, etc.
02 Choose the right servo motor
Servo motor (servo motor) refers to the power device that drives the load component in the servo system, and is a kind of auxiliary motor indirect speed change device. In the automatic control system, it is used as an actuator, and has the characteristics of small electromechanical time constant and high linearity. It can convert the received electrical signal into angular displacement or angular velocity output on the motor shaft.
1. Installation dimension of motor
You can refer to the installation of which brand of servo motor used before the equipment, and pay attention to the flange, shaft diameter, keyway size, oil seal, whether it is equipped with brakes, etc.
2. The maximum speed of the motor
Motor selection first consider the maximum speed of the motor, the motor speed should be strictly controlled within the rated speed of the motor.
3. Rated torque of motor
The torque of the motor working for a long time should be strictly controlled at 70-80% of the rated torque of the motor. Allow short time instantaneous overload 2-3 times for 1-2s.
In the actual servo motor selection process, the rated torque of the motor is considered first, followed by the power, and finally the speed.
So that's all for today's introduction. I believe that through the above introduction, everyone has a basic understanding of the selection of servo systems. I hope that through this article, everyone can be inspired in the process of servo system selection. Want to know more about servo system selection and product information, please pay attention to the public number -- Aotong Aicortech.
This website already supports IPV4 / IPV6 bidirectional access