Research On Several Issues Of High-Speed Electric Multiple Units Train Network Control

With the rapid development of Chinese High-speed Electric Multiple Unit (EMU) and the depth of its research, the train network control system takes more and more attention of researchers as one of its key technologies. The control system based on the train communication network replacing the original and traditional centralized computer control, has the advantages of interactive, less cabling, easy to expand and maintenance, the system's flexibility, high reliability, and etc. Meanwhile, the design and analysis of the control system confronts with more complex factors because of the involvement of the train communication network and the adaptive theory of the train communication network control system analysis and design must be utilized. This dissertation does the research and analysis around the train network control performance, stability, real-time and real-time scheduling features, combined with the digestion and absorption of CRH3high-speed EMU as well as the development of the CRH380BL EMU in Tangshan Railway Vehicles Co., Ltd.TCN network transmission medium using shielded twisted pair, is the bearer of the high-speed EMU network control signal, and plays a vital role in the stability of the control system. Aiming at evaluating the performance of the transmission media-twisted pairs used for TCN network, including attenuation, near-end crosstalk, impedance and delay. It is often occurred that the MVB and WTB cable does not meet the performance and cannot be qualitatively judged the cause of the problem in CRH3EMU debugging process, which is based, the distributed parameter model of the twisted pair is derived and established in this dissertation, then using transmission line theory to solve the insertion loss, delay, offset and near-end crosstalk. Through the model simulation of the transmission line used in the high-speed EMU, and a comparative study and experimental results is researched. In order to study the impact of wiring on the transmission line characteristics, changing the layout of the wire, calculating the parameters, and comparison, simulation and analysis is obtained. Then changing the single characteristic parameters and doing simulation research to study the characteristic parameters of the deterioration of the performance. Experimental and simulation results show that:the derivate model has very high applicability, and which can be used for analysis and layout optimization of twisted-pair on the high-speed EMUs; Disturbance of the characteristic parameters deteriorates the transmission medium performance, which make the performance margin decreased. The extent and scope of performance deterioration varies form the difference among the parameters changing.This dissertation presents a TCN network research method based on OPNET simulation software for the characteristics of CRH3high-speed EMU TCN control network, combined with periodic polling strategy adopted in CRH3high-speed EMU, derives and establishes the MVB model and WTB inauguration model. Data throughput, delay, and collision characteristics have been the focus of the network performance assessment, also for the development of new EMU control network. According to the process scheduling and message data response mechanism of the MVB network, the simulation tests are realized in the different simulation scenarios. Under the Conditions of different message data sending node numbers and different messages data sending rate, the effects on the MVB network performance are researched. In order to research the control procedure in train coupling process of CRH3high-speed EMU, WTB inauguration mechanism is in-depth studied, and the simulation under normal inauguration mode and the WTB coupling process is done to study the adaptive features of WTB marshaling. The MVB controller encoding and decoding algorithms are achieved. Through the usage of FPGA scheme replacing the MVB controller and inter-connect verification with the dedicated MVB card, the MVB data link layer protocol mechanism is researched.Due to the usage of the communication network in the control system, the delay become one of factors had to be considered. Unreasonable delay setting or inaccurate estimate will affect the system stability margin as well as unstable, and lead to locking some features of the train control system. We have seen the phenomenon of high-voltage traction system locking in the testing process of CRH3high-speed EMU because of inaccurate delay calculation and setting. This dissertation has researched on the stability of networked control systems from different perspective using Lyapunov theory, matrix theory and linear matrix inequality, and derived the maximum allowable network delay and stability conditions to asymptotically stable the networked control systems. The results show that as long as actual network control system transmission delay less than the maximum allowable network delay or meeting the network control system stability theorem, the closed-loop network control system is always asymptotically stable. Therefore, the appropriate network type and control algorithms should be designed against the practical conditions to stable the network control system. The state observer and controller design theory based on the output feedback has been given against the deterministic delay network control systems.In high-speed EMU this is more systems need to be controlled, which caused a significant increase of the control port and which is also inconsistent in the length of the port and the characteristic period, therefore reliable scheduling polling is required for train communication network. This dissertation proposes a new train network period scheduling algorithm against the lack of uneven periodic bus-load utilization in CRH3high-speed EMU polling strategy. The multi-level scheduling optimization algorithm as the target on bus load rate uniformity is obtained by calculating the high-speed EMU period-data load rate. According to the characteristics of MVB polling periodic table, some hierarchical constraints are added and the Local objective function take place of global objective function in the solution process. The operational efficiency of the algorithm is greatly improved. This dissertation has also demonstrated the relationship between the rate monotonic algorithm, genetic algorithm and multi-constraint conditions evenness priority scheduling algorithm, in order to show that the optimization algorithm has great advantages under the conditions. The schedulability analysis for the optimization algorithm is processed and it shows the validity of the results after the periodic polling table is optimized. The simulation results further confirm that the optimization algorithm has achieved optimum uniformity of the load information. The event schedule model based on OPNET simulation is proposed according to the event arbitration algorithm for non-periodic data.Finally, the research conclusions are presented and the future research works are discussed.