Reserch On Key Issues Of Netxwork Control For Electric Multiple Units Based On UIC556 Standard

Network control technology is one of the most core technology of EMU.Compared with traditional and point-to-point control mode,train network control reduces system wiring and enhances maintainability and interaction.In the meanwhile,it has other advantages,such as high fault diagnosis ability,a strong resource sharing capability,and so on.It is conducive to realize cooperative control between on-board subsystems and between coupled trains.Although train network control has many advantages,it brings some new issues and new challenges.Firstly,different types of EMUs in our country can not achieve interconnection,intercommunication and interoperability via train communication network.It reduces train operation efficiency.Secondly,when EMU is running in coupled mode,due to the large number of nodes and data transmitted on the network,it leads to transmission time-delay of real-time data.The reliability and stability of control performance will be affected.Finally,electromagnetic environment outside and inside of EMU is very complex.Electromagnetic interference is inevitably coupled to communication cables at all levels of network control system.This will cause control signal waveform distortion,data packet loss,and even electronic equipment damage.1.In order to solve the issue of interconnection,intercommunication and interoperability between different types of EMUs,research on the software architecture and core algorithms of UIC556 standard is carried out.The rationality and correctness of theoretical analysis are verified by semi-physical simulation experiments.2.The production principle of process data transmission time-delay on EMU coupled control network is analyzed.The time-delay measurement is carried out by using the method of' Round-trip delay(RTT).Taking into account real-time and accuracy,a Auto Regressive(AR)model is proposed to predict network time-delay.Akaike information criterion(AIC)is used to determine AR model order.Based on the principle of least mean square error,Yule-walker equation is solved by Levison-Durbin fast recursive algorithm in order to identify AR model parameters.Matlab simulation results show that the time-delay predictive value can fit well with measured data and has an high prediction accuracy.3.A improved and fast Generalized Predictive Control(GPC)algorithm is proposed to compensate time-delay of EMU coupled control network.According to time-delay estimated value from AR model,the minimum prediction horizon and control horizon of prediction CARIMA model can be determined.The improved algorithm can avoid solving Diophantine equations.Experiment results show that the proposed algorithm can effectively reduce adverse effects caused by time-delay.The system output can be a good tracking input reference.The algorithm has advantages of high computation efficiency,short response time,small overshoot and good robustness.4.For crosstalk issue of communication cables used for EMU network control,telegraph equations of the multi-conductor transmission line under lumped source excitation are presented.The calculation method of distribution parameters of transmission line is also given.Through using generalized two-port network theory,the terminal solve of electromagnetic coupling response of communication cables is computed in the frequency domain.By using Finite Difference Time Domain(FDTD)method,iterative calculation model of electromagnetic coupling response is derived.In the frequency domain and time domain,simulation analysis of influence factors on the crosstalk of communication cables are carried out.Protective measures to suppress the crosstalk of communication cables are put forward.5.In view of the issue of electromagnetic radiation interference to network control communication cables under EMU complex electromagnetic environment,telegraph equations of multi-conductor transmission line under distributed source excitation are presented.The method for calculating transfer impedance of braided shielding is also presented.Based on Agrawal model,the distribution voltage source of transmission line system composed of communication cables and shielding layer is calculated.FDTD iterative model to solve radiation coupling response is derived.Factors affecting radiation coupling are analyzed by simulation experiments.6.Based on the principle of equivalent magnetic current,equivalent magnetic current on the rectangular aperture is solved by triangular and pulse functions method.Coupling electric field in the cable tank is calculated.To solve the issue of multiaperture coupling of cable tank,a linear superposition calculation method is given.The influence of electromagnetic interference on communication cables in the cable tank is analyzed by simulation experiment.7.For electromagnetic compatibility issue of communication cables in UIC harness between coupled EMUs,a simplified analysis method based on equivalent impedance of transmission lines is proposed.The simulation results show that before and after the simplification,responses of conduction and radiated interference on the communication cables are basically the same.And simulation time and resource occupancy significantly are reduced.8.Above relevant research results are applied to a train network control system.Train running result verifies the validity of theoretical researches.