A servo system is a feedback control system used to precisely follow or reproduce a process. It's an automatic control system that enables the output controlled variables, such as the position, orientation, and state of an object, to follow any changes in the input target (or given value). Its main task is to amplify, transform, and regulate power according to control commands, making the torque, speed, and position control of the drive device highly flexible and convenient.
A servo drive is part of a servo system and is used to control a servo motor. Its function is similar to that of a frequency converter for a regular AC motor, and it is mainly used in high-precision positioning systems. Generally, it controls the servo motor through three methods: position, speed, and torque, achieving high-precision positioning of the transmission system. Currently, it represents a high-end product in transmission technology.
Choosing a suitable servo drive requires considering various aspects, primarily based on system requirements. Before selecting a drive, it's essential to analyze system needs such as size, power supply, power consumption, and control method to guide the selection process. Below, we'll examine the various parameters of a servo drive.
1. Continuous current, peak current;
2. Power supply voltage, control unit power supply voltage;
3. Supported motor types and feedback types;
4. Control mode and command acceptance method;
5. Communication Protocol
6. Digital I/O
Based on this information, we can roughly select a servo driver that matches the motor. In addition, we should also pay attention to the working environment, temperature and humidity, and whether the installation dimensions are suitable.
Choosing a servo driver involves considering not only its compatibility with the motor but also the control method. Servo drivers offer three control modes: position, speed, and torque. Torque and speed modes allow torque to be set via external analog inputs or communication commands, while position mode determines speed and distance by the frequency and number of pulses. In torque mode, the motor outputs a fixed torque, with no control over position or speed. Position mode provides strict control over both speed and position and is typically used in positioning devices. The appropriate control mode should be selected based on system requirements and the type of upper-level control.
Modern servo drives are becoming increasingly intelligent, supporting various types of servo motors and compatible with multiple feedback methods. They can receive analog signals, PWM, pulse + direction signals, and software commands, and support communication protocols such as CANopen and EtherCAT. They offer three-loop control and commutation functions, as well as intelligent one-button tuning. They are very convenient to use, offer high control precision, significantly improve system performance, and save developers considerable time.
