The rapid development of power electronic technology, computer technology and communication technology will definitely promote the rapid development of electric actuators. Mechatronics will replace the split structure; intelligent communication will replace analog signals; the control accuracy will become higher and higher, and the use environment will become more and more The wider it is; the more powerful the functions and the higher the reliability, in order to adapt to the requirements of the constantly developing automatic control.
1. Bus and network
Abroad, factory automation engineering technology based on industrial local area network technology has been greatly developed in the last ten years. As one of the automatic instruments in automatic control, electric actuators should also have standard serial communication to adapt to this development trend. Interface (such as RS-232 or RS-422 interface, etc.) and a dedicated LAN interface to enhance the interconnection ability between it and other control equipment, only a single cable or optical cable, you can connect several or even dozens of electric. The actuator is connected with the host computer to become the entire CNC system. Fieldbus is a serial, digital, multipoint communication data bus between field equipment/instruments installed in the production process area and automatic control devices/systems in the control room. As the development direction of the control system in the future, the fieldbus enterprise network makes it possible to combine it with the Interent due to its openness, networking and other advantages, and the application of fieldbus technology to electric actuators has become an inevitable trend. The application of fieldbus technology replaces the traditional 4-20mA analog signal, realizes the remote monitoring of electric actuators, the transmission of status, faults, and parameter information, completes the remote parameterization work, improves its reliability, reduces the system and Engineering cost. At present, the influential field buses mainly include PROFIBUS, FF, HART, CAN and so on. In fact, the current intelligent electric actuators abroad generally have fieldbus interfaces, and my country has also developed some intelligent actuators with fieldbus interfaces.
2. Digitization and intelligence
Intelligentization is the current trend of all industrial control equipment. Low-cost microcontrollers and new high-speed microprocessors will fully replace the control units of electric actuators based on analog electronic devices, so as to realize a completely digital control system. The fully digital implementation turns the original hardware control into software control, so that advanced algorithms of modern control theory (such as: optimal control, artificial intelligence, fuzzy control, neural network, etc.) can be applied to electric actuators. Improve control performance. Traditional electric actuators are generally regarded as linear systems, consisting of amplifying and integrating links. But in fact, most of the actuator parameters will change significantly during operation. The application of parameter scheduling and model identification adaptive control will greatly improve the control performance of electric actuators. Compared with pneumatic and hydraulic actuators, smart electric actuators with simple wiring, powerful functions and reliable use will continue to expand the scope of application.
3. Miniaturization and electromechanical integration
The high integration of power electronics, the use of single-chip microcomputers and the use of some powerful modules have made the size of electric actuators smaller and smaller, making them smaller and lighter. At present, the intelligent electric actuator generally installs the entire control loop in a field instrument, and installs the servo motor and the field instrument controller as one. The integration of electric actuators simplifies the installation and commissioning of the actuators; the entire control loop is installed in a field instrument, which reduces the impact on the system due to factors such as leakage and interference in signal transmission. The reliability of the system.
