The Control Strategy Research Of Networked Control System Based On Ethernet

With the rapid development of network technology,the network control system based on Ethernet breaks through the limitations of fieldbus control system,becomes a new developing direction of network control system,and is widely used in various fields of production and life.At the same time,the network time delay,date packet loss and scheduling information such as the problems existing in the network control system are still the research hotspots based on Ethernet network control system.Among them,the network time delay is the main problem affecting the network control system based on Ethernet.This paper focuses on network time delay problem and do the following works:1?Time delay analysis.This paper,as detailed as possible,analyzes the structure and the forming reason of time delay of the network control system based on traditional Ethernet and switched Ethernet,contrasts the time delay in the NCS based on Ethernet with other control system and analyzes in different time delay characteristics through the simulation experiment of TrueTime toolbox.2?Time delay compensation.On the basis of the above time delay simulation experiment,this paper puts forward the following two time delay compensation strategys based on the time delay characteristics of Ethernet:(1)In view of the random long delay in network control system based on traditional Ethernet,Generalized Predictive Control algorithm is applied to the system,and the algorithm is improved on the basis of the traditional algorithm in combination with the minimum variance control though,and avoids solving Diophantine equation and reduces the computing time,improves the performance of system control.(2)In view of the random short delay in network control system based on switched Ethernet,this paper proposes a design method of state observer that can compensate the random time delay,and further proves that under the condition of the system status cannot be directly measured the method can effectively compensate random time delay and ensure the stability of the closed-loop system.