The control system in the 21st century will be the combination of network and control. The research of networked control system (NCS) has become one of the frontier topics in the field of automation. As a part of the system, the communication network is embedded into the control system, which greatly enriches the industrial control technology and means, and greatly changes the system structure, control method and man-machine cooperation method between the automation system and the industrial control system. At the same time, it also brings some new problems, such as the coupling of control and communication, time delay, information scheduling and so on. Method, distributed control mode and fault.
With the emergence of these new problems, the control methods and algorithms of automatic control theory in the network environment need to be innovated. With the development of computer technology, communication technology and network technology, the traditional control field began to develop in the direction of networking. A networked control loop is a networked control system. It is characterized in that the command and feedback of the control system are transmitted in the form of packets in the network. The most important feature of networked control system is that it connects cyberspace and physical space, so it can perform many tasks over a long distance.
Moreover, the signals of the networked control system are transmitted through the common network (and wire), which saves unnecessary wiring, reduces the complexity of the system, and reduces the cost of designing and erecting the system. To add sensors, controllers or actuators to adjust or update the system, it can also be achieved at a lower cost without changing the main architecture of the system. The biggest feature of networked control system is that each controller can share data efficiently, so it can integrate the overall information in a large physical space and make wise decisions.
Networked control systems can be used in many fields, such as space and land exploration, entering dangerous areas and related operations, factory automation, remote diagnosis and troubleshooting, experimental equipment, household robots, aircraft, vehicles, factory monitoring, nursing centers and remote operations. However, networked control system can be applied in many occasions in theory, but there are few cases of real practical application. Until the concept of industry 4.0 becomes more and more popular, this technology is gradually being paid attention to.
Firstly, the traditional control field is undergoing unprecedented changes and began to develop in the direction of networking. The structure of control system has developed from computer centralized control system (CCS) to the second generation distributed control system (DCS), and then to fieldbus control system (FCS). The requirements of large amount of data and high-speed transmission, such as image and voice signals, also gave birth to the combination of industrial Ethernet and control network.
Secondly, this networked trend of industrial control system integrates many popular technologies such as embedded technology, multi standard industrial control network interconnection, wireless technology and so on, expands the development space of industrial control field and brings new development opportunities. However, the most critical and important issue of distributed networked control system is to meet the requirements of system reliability and dependency, and to ensure that the system should have high performance within its working range. This part has become more and more complex. Therefore, networked error detection and diagnosis technology has attracted more and more attention, and these are also the core of monitoring system performance in industrial and other scenarios.
Promoting industrialization with information technology is not only a powerful guarantee for the sustained and rapid development of the national economy, but also an important means for the structural transformation of the traditional industrial system. As the representative of information technology, the combination of network technology and industrial control system will greatly improve the level of control system, change the relatively closed enterprise information management structure of existing industrial control system, and meet the needs of comprehensive automation management of modern enterprises. Network technology has promoted the transformation of the structure of traditional industrial control system.
Its significance lies in the integrated fieldbus, Ethernet, interconnection of various industrial control networks, embedded technology and wireless communication technology. In the industrial control network, it not only ensures the requirements of the original stability and real-time control system, but also improves the openness and interoperability of the system, and improves the adaptability of the system to different environments. In today’s economic globalization, this industrial control system network and its composition mode enable enterprises to adapt to the unprecedented fierce market competition, help speed up the development of new products, reduce production costs and improve information services, and have broad development prospects.