Modeling And Control Of A Kind Of Networked Control Systems With Data Packet Disordering

With the rapid development of computer and network technology, the networked control systems (NCSs), which is based on the high speed communication network, has become one of the focus issues in current international control field. The research on NCSs has important theoretical meanings and extensive application prospects. Compared with the traditional control system, this networked control system can share information resource, develop remote operation, be easy to maintain and save time. NCSs have become the topic, which plays an important role in the modern industrial and commercial fields, where the real networks are used to exchange information and control signals. However, the insertion of the network in the closed-loop systems brings many new issues inevitably, such as network-induced delays, data packet dropouts, data packet disordering, multiple-packet transmissions, clock synchronization and so on. These issues may degrade the performance of control systems and may even destabilize the system, which make the analysis and synthesis of NCSs complex. Therefore, NCSs have received considerable attention by researchers in recent years. And the research in network-induced delays and data packet dropouts obtains some results, but the research about data packet disordering is much less. With the popularity of internet, disordering for network is shown on increasingly common phenomenon. In the actual control system, as a result of packet disordering greatly reduced the performance index of system. Therefore, it is necessary to study the disordering for the networked control system.This paper, based on the understanding of various problems in NCSs, carefully analyses the reasons of data packet disordering. Aiming at the discrete controlled object, This paper supposes that the network-induced delay is long delay, and it gives two discrete models through two methods of Probability, in which we can directly find out the phenomenon of data packet disordering, and it analyses the system stability and gives the controller, finally it gives a numerical example to illustrate the effectiveness of the method. In the paper, it constructs the model from the normal distribution prediction and Markovian random stability.Firstly, this paper uses the normal distribution to predict the delay, according to the general discrete object, and accounts the excursion number by the delay to get the model. In this model, we can directly find out the packet disordering. And the paper analyses the stability and gets the controller, finally it gives a numerical example to illustrate the effectiveness of the method.What is more, based on induced-delay satisfying Markovian characteristics, this paper transforms the system model into the closed-loop Markovian jump linear system. And it gets a system model, which is made of many subsystems. In these subsystems, the selection between the inputs can reflect the packet disordering. Further more, the stability of the closed-loop system is discussed; and an LMI method is given for the controller design. Finally, a numerical example is given to illustrate the effectiveness of the method.