Switched Ethernet-based Network Control System For Scheduling Research

Networked Control System (NCS) is a kind of computer control system which put network as a part of closed-loop control system. Ethernet transfer rate's rapid increasing and development of exchangeable technology has greatly facilitated the exchange of switched Ethernet-based NCS applications and development. In this paper, switched Ethernet-based network control system was studied as follows:1) Studied issues of latency and congestion on the switched Ethernet network of NCS. Introduced the characteristics of switched Ethernet and analyzed the composition of the network delay. Introduced congestion control problem which affected the network quality of service and network quality of control, analyzed the causes of network congestion and common solutions. Through simulation, conclusions that applying DiffServ technology can effectively alleviate the network congestion and ensure that the QOS requirements of control data are given, studied in experiment of queue scheduling methods including FIFO, PQ, SRR etc, comparatively analyzing the characteristics of the network delay of the scheduling method.2) Queue scheduling algorithms which are based on quality control and differentiated services technology were studied. A priority-based control of Ethernet information classification of static scheduling methods was improved. A scheduling method which can change dynamic real-time control information and transmission queue priority based on a control of error was presented. Finally, control effect was simulated in the experimental platform of networked control systems.3) A method which uses weighted error to determine the deadband threshold method to reduce the deadband limit cycle performance of the control and compensate data loss which caused by the control system performance by forecasting is given through simulation to the deadband scheduling problem in networked control system. Finally, control effect was simulated in the experimental platform of networked control systems.4) Designed and realized NCS simulation platform which is based on switched Ethernet system, Introduced the structure of experimental platform, the original network simulation system and network design key technologies of the experimental platform software, Introduced the design of simulation software and Ethernet priority scheduling method.